Document:

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                                                                   EXHIBIT (10b)

                              EMPLOYMENT AGREEMENT

         AGREEMENT, made this 20th day of April, 2000, by and between Yellow
Corporation, a Delaware corporation ("Yellow"), and Herbert A. Trucksess, III
(the "Executive").

                                   WITNESSETH

         WHEREAS, the Board of Directors of Yellow has approved the employment
of the Executive on the terms and conditions set forth in this Agreement; and

         WHEREAS, the Executive is willing, for the consideration provided, to
enter into employment with Yellow on the terms and conditions set forth in this
Agreement;

         NOW, THEREFORE, the parties, intending to be legally bound, agree as
follows:

         1.  Employment. Yellow hereby agrees to employ the Executive, and the
             Executive hereby accepts such employment, upon the terms and
             conditions set forth in this Agreement.

         2.  Term. The term of this Agreement shall be for two (2) years from
             the date hereof (the "Effective Date"), with said term renewing
             daily, and ending on the date of termination of the Executive's
             employment determined pursuant to Section 5, 6, 7, 9 or 10,
             whichever shall be applicable.

         3.  Position and Duties. The Executive shall serve as President,
             Regional Carrier Group, and shall have such responsibilities and
             authority as commensurate with such offices and as may from time to
             time be prescribed by or pursuant to Yellow's bylaws. The Executive
             shall devote

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             substantially all of his working time and efforts to the business
             and affairs of Yellow.

         4.  Compensation. During the period of the Executive's employment,
             Yellow shall provide the Executive with the following compensation
             and other benefits:

             (a) Base Salary. Yellow shall pay to the Executive base salary at
                 the rate of $350,000 per annum, retroactive to February 1,
                 2000, which shall be payable in accordance with the standard
                 payroll practices of Yellow. Such base salary rate shall be
                 reviewed annually in accordance with Yellow's normal policies
                 beginning in calendar year 2001; provided, however, that at no
                 time during the term of this Agreement shall the Executive's
                 base salary be decreased from the rate then in effect except
                 (i) in connection with across-the-board reductions similarly
                 affecting substantially all senior executives of Yellow or (ii)
                 with the written consent of the Executive.

             (b) Annual Bonus. The Executive shall participate in a bonus
                 program established and maintained by Yellow pursuant to which
                 a threshold award for each fiscal year is 13.75% of the
                 Executive's base salary; a target award is 55% of base salary;
                 and a maximum award is 110% of base salary in respect of each
                 fiscal year of Yellow commencing with 2000, provided that any
                 payment under such award shall be conditioned upon satisfaction
                 of the threshold. The criteria for establishment of the
                 threshold and

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                 target and the parameters for payments at, above or below the
                 target shall be determined annually by the Compensation
                 Committee of the Board of Directors of Yellow. At least 80% of
                 the criteria established by the Compensation Committee which
                 would result in a payment of 55% of base salary to the
                 Executive shall be based on specific measurements of financial
                 performance of Yellow during the applicable fiscal year and the
                 remaining percentage may be based on non-financial criteria.

             (c) Stock Options. Yellow has previously granted to Executive
                 options to purchase 290,000 shares of Common Stock of Yellow in
                 five separate grants, each grant having an option term of ten
                 years and an option price per share equal to the closing price
                 of a share of Common Stock of Yellow as reported on the NASDAQ
                 National Market System on the date of each grant, and each
                 grant vesting over four years in equal annual installments.
                 With respect to succeeding years, the Compensation Committee of
                 the Board of Directors of Yellow shall determine the number of
                 stock options, if any, to be granted to the Executive and the
                 terms and conditions of any such options.

             (d) Supplemental Retirement Benefits. Yellow shall provide
                 Executive with supplemental retirement benefits in accordance
                 with this subsection (d) and Appendix A pursuant to which the
                 Executive shall receive from Yellow upon his termination of
                 employment with Yellow, the difference between (i) the monthly
                 benefit that

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                 he would have received under Section 4.4 of the Yellow Freight
                 Office, Clerical, Sales and Supervisory Personnel Pension Plan
                 (the "Pension Plan") (calculated as a single life annuity
                 payable commencing at his Normal Retirement Date as defined
                 under the Pension Plan with an actuarial reduction if payment
                 commences prior to his Normal Retirement Date) using 16 years
                 of Credited Service as defined under the Pension Plan plus his
                 actual Credited Service credited under the Pension Plan from
                 June 1, 1994, the date of Executive's commencement of
                 employment with Yellow and using Compensation as defined in
                 Section 2.1(h) (2) of the Pension Plan, but without any
                 reduction under Section 401(a) (17) of the Internal Revenue
                 Code of 1986, as amended (the "Code") and (ii) the monthly
                 benefit actually payable to the Executive under Section 4.4 of
                 the Pension Plan, calculated at the time the Executive
                 commences payment of a Vested Pension under the Pension Plan.
                 Following the termination of Executive's employment, the
                 supplemental retirement benefit described in this subsection
                 (d) shall be payable no sooner than the earliest date of
                 Executive's eligibility to receive retirement benefits under
                 the Plan measured from his date of termination with Executive
                 having the option of deciding when to commence payments
                 following achieving such eligibility, subject to actuarial
                 reduction for payments commencing prior to Executive's Normal
                 Retirement Date, and shall continue until the Executive's
                 death. Upon the

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                 Executive's death, if at the time of his death payments had
                 already commenced under this Supplemental Retirement Benefit
                 and if he is survived by and still married to the person who
                 was his spouse on June 1, 1994, the monthly supplemental
                 retirement benefit payable to the Executive during his life
                 shall continue to said surviving spouse until her death. If at
                 the time of his death, the Executive had not yet qualified for
                 payment of a retirement benefit under the Pension Plan or if
                 Executive had qualified but payments had not yet commenced, if
                 he is survived by and still married to the person who was his
                 spouse on June 1, 1994, the Supplemental Retirement Benefit
                 shall be payable to said spouse no sooner than the earliest
                 date that Executive would have been eligible to receive
                 retirement benefits under the Plan measured from his date of
                 death with said spouse having the option of deciding when to
                 commence payments following the date that Executive would have
                 achieved such eligibility, subject to actuarial reduction for
                 payments commencing prior to the date that Executive would have
                 reached his Normal Retirement Date, and shall continue to said
                 surviving spouse until her death. If the Executive at the time
                 of his death is neither survived by or not married to the
                 person who was his spouse on June 1, 1994, no further
                 supplemental retirement benefits shall be payable under this
                 subsection (d) following his death. The Executive acknowledges
                 that these supplemental retirement benefits are an

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                 element of the compensation to be paid for his services and not
                 an unfunded plan of deferred compensation within the meaning of
                 Section 201 of the Employee Retirement Income Security Act, as
                 amended.

             (e) Other Benefits. In addition to the compensation and benefits
                 otherwise specified in this Agreement, the Executive (and, if
                 provided for under the applicable plan or program, his spouse)
                 shall be entitled to participate in, and to receive benefits
                 under, Yellow's employee benefit plans and programs that are or
                 may be available to senior executives generally and on terms
                 and conditions that are no less favorable than those generally
                 applicable to other senior executives of Yellow. At no time
                 during the term of this Agreement shall the Executive's
                 participation in or benefits received under such plans and
                 programs be decreased except (i) in connection with
                 across-the-board reductions similarly affecting substantially
                 all senior executives of Yellow or (ii) with the written
                 consent of the Executive.

             (f) Expenses. The Executive shall be entitled to prompt
                 reimbursement of all reasonable expenses incurred by him in
                 performing services hereunder, provided he properly accounts
                 therefore in accordance with Yellow's policies.

             (g) Office and Services Furnished. Yellow shall furnish the
                 Executive with office space, secretarial assistance and such
                 other facilities

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                 and services as shall be suitable to the Executive's position
                 and adequate for the performance of his duties hereunder.

         5.  Termination of Employment by Yellow.

             (a) Cause. Yellow may terminate the Executive's employment for
                 Cause if the Executive willfully engages in conduct which is
                 materially and demonstrably injurious to Yellow or if the
                 Executive willfully engages in an act or acts of dishonesty
                 resulting in material personal gain to the Executive at the
                 expense of Yellow. Yellow shall exercise its right to terminate
                 the Executive's employment for Cause by (i) giving him written
                 notice of termination at least 30 days before the date of such
                 termination specifying in reasonable detail the circumstances
                 constituting such Cause; and (ii) delivering to the Executive a
                 copy of a resolution duly adopted by the affirmative vote of
                 not less than a majority of the entire membership of the Board
                 of Directors after reasonable notice to the Executive and an
                 opportunity for the Executive and his counsel to be heard
                 before the Board of Directors, finding that the Executive has
                 engaged in the conduct set forth in this subsection (a). In the
                 event of such termination of the Executive's employment for
                 Cause, the Executive shall be entitled to receive (i) his base
                 salary pursuant to Section 4(a) and any other compensation and
                 benefits to the extent actually earned pursuant to this
                 Agreement or any benefit plan or program of Yellow as of the
                 date of such termination at the normal time for

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                 payment of such salary, compensation or benefits, but not
                 including the Supplemental Retirement Benefit described in
                 Section 4(d), and (ii) any amounts owing under Section 4 (f).
                 In addition, in the event of such termination of the
                 Executive's employment for Cause, all outstanding options held
                 by the Executive at the effective date of such termination
                 which had not already been exercised shall be forfeited. Except
                 as provided in Section 11, the Executive shall receive no other
                 compensation or benefits from Yellow.

             (b) Disability. If the Executive incurs a Permanent and Total
                 Disability, as defined below, Yellow may terminate the
                 Executive's employment by giving him written notice of
                 termination at least 30 days before the date of such
                 termination. In the event of such termination of the
                 Executive's employment because of Permanent and Total
                 Disability, (i) the Executive shall be entitled to receive his
                 base salary pursuant to Section 4(a) and any other compensation
                 and benefits to the extent actually earned by the Executive
                 pursuant to this Agreement or any benefit plan or program of
                 Yellow as of the date of such termination of employment at the
                 normal time for payment of such salary, compensation or
                 benefits, including specifically the Supplemental Retirement
                 Benefit described in Section 4(d), and any amounts owing under
                 Section 4(f), and (ii) all outstanding stock options held by
                 the Executive at the time of his termination of

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                 employment shall become immediately exercisable at that time,
                 and the Executive shall have one year from the date of such
                 termination of employment to exercise any or all of such
                 outstanding options (but not beyond the term of such option).
                 For purposes of this Agreement, the Executive shall be
                 considered to have incurred a Permanent and Total Disability if
                 he is unable to engage in any substantial gainful employment by
                 reason of any materially determinable physical or mental
                 impairment which can be expected to result in death or which
                 has lasted or can be expected to last for a continuous period
                 of not less than 12 months. The existence of such Permanent and
                 Total Disability shall be evidenced by such medical
                 certification as the Secretary of Yellow shall require and
                 shall be subject to the approval of the Compensation Committee
                 of the Board of Directors of Yellow.

             (c) Without Cause. Yellow may terminate the Executive's employment
                 at any time and for any reason, other than for Cause or because
                 of Permanent and Total Disability, by giving him a written
                 notice of termination to that effect at least 30 days before
                 the date of termination. In the event of such termination of
                 the Executive's employment without Cause, the Executive shall
                 be entitled to the benefits described in Section 8.

         6.  Termination of Employment by the Executive.

             a.  Good Reason. The Executive may terminate his employment for
                 Good Reason by giving Yellow a written notice of
                 termination at

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                 least 30 days before the date of such termination specifying in
                 reasonable detail the circumstances constituting such Good
                 Reason. In the event of the Executive's termination of his
                 employment for Good Reason, the Executive shall be entitled to
                 the benefits described in Section 8. For purposes of this
                 Agreement, Good Reason shall mean the failure of Yellow in any
                 material way either (i) to pay or provide to the Executive the
                 compensation and benefits that he is entitled to receive
                 pursuant to this Agreement by the later of (A) 60 days after
                 the applicable due date or (B) 30 days after the Executive's
                 written demand for payment, or (ii) to maintain the titles,
                 positions and duties of the Executive commensurate with those
                 titles and positions and as required by this Agreement except
                 with the Executive's written consent, or (iii) Executive's
                 receipt of notice from Yellow of the cut-off of the automatic
                 renewal of the term of this Agreement as described in Section 2
                 above.

             b.  Other. The Executive may terminate his employment at any time
                 and for any reason, other than pursuant to subsection (a)
                 above, by giving Yellow a written notice of termination to that
                 effect at least 30 days before the date of termination. In the
                 event of the Executive's termination of his employment pursuant
                 to this subsection (b), the Executive shall be entitled to
                 receive (i) his base salary pursuant to Section 4(a) and any
                 other compensation and benefits to the extent actually earned
                 by the Executive

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                 pursuant to this Agreement or any benefit plan or program of
                 Yellow as of the date of such termination at the normal time
                 for payment of such salary, compensation or benefits including
                 specifically the Supplemental Retirement Benefit described in
                 Section 4(d), and (ii) any amounts owing under Section 4(f). In
                 the event of the Executive's termination of his employment
                 pursuant to this subsection (b), all outstanding options held
                 by the Executive not previously exercised by the date of
                 termination shall be forfeited. Except as provided in Section
                 10, the Executive shall receive no other compensation or
                 benefits from Yellow.

         7.  Termination of Employment By Death. In the event of the death of
             the Executive during the course of his employment hereunder, (i)
             the Executive's estate shall be entitled to receive his base salary
             pursuant to Section 4(a) and any other compensation and benefits to
             the extent actually earned by the Executive pursuant to this
             Agreement or any other benefit plan or program of Yellow as of the
             date of such termination at the normal time for payment of such
             salary, compensation or benefits, and any amounts owing under
             Section 4(f), (ii) any death benefit due under the Pension Plan and
             any death benefit due under Section 4(d) shall be paid to the
             Executive's spouse as provided under Section 4(d) and (iii) all
             outstanding stock options held by the Executive at the time of his
             death shall become immediately exercisable upon his death, and the
             Executive's spouse or, if predeceased, the Executive's estate,
             shall have

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             one year from the date of his death to exercise any or all of such
             outstanding options (but not beyond the term of such option).

         8.  Benefits Upon Termination Without Cause or Good Reason If the
             Executive's employment with Yellow shall terminate (i) because of
             termination by Yellow pursuant to Section 5(c) and not for Cause or
             because of Permanent and Total Disability, or (ii) because of
             termination by the Executive for Good Reason pursuant to Section
             6(a), the Executive shall be entitled to the following:

             (a) Yellow shall pay to the Executive his base salary pursuant to
                 Section 4 (a) and, subject to the further provisions of this
                 Section 8, any other compensation and benefits to the extent
                 actually earned by the Executive under this Agreement or any
                 benefit plan or program of Yellow as of the date of such
                 termination at the normal time for payment of such salary,
                 compensation or benefits.

             (b) Yellow shall pay the Executive any amounts owing under Section
                 4(f).

             (c) Yellow shall pay to the Executive as a severance benefit an
                 amount equal to twice the sum of (i) his annual rate of base
                 salary immediately preceding his termination of employment, and
                 (ii) the target bonus payable pursuant to subsection (d) below.
                 Such severance benefit shall be paid in a lump sum within 30
                 days after the date of such termination of employment.

             (d) Yellow shall pay to the Executive his target bonus under
                 Yellow's target bonus plan for the fiscal year in which his
                 termination of

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                 employment occurs as if the target had been exactly met. Such
                 payment shall be made in a lump sum within 30 days after the
                 date of such termination of employment, and the Executive shall
                 have no right to any further bonuses under said program.

             (e) The Executive shall become eligible for payment of the
                 supplemental retirement benefits pursuant to Section 4(d), and
                 Yellow's nonqualified defined contribution plans. Payment of
                 benefits under such plans, and under the Pension Plan and
                 Yellow's qualified defined contribution plans, shall be made at
                 the time and in the manner determined under the applicable
                 plan.

             (f) During the period of 24 months beginning on the date of the
                 Executive's termination of employment, the Executive (and, if
                 applicable under the applicable program, his spouse) shall
                 remain covered by the employee benefit plans and programs that
                 covered him immediately prior to his termination of employment
                 as if he had remained in employment for such period, provided,
                 however, that there shall be excluded for this purpose any plan
                 or program providing payment for time not worked (including
                 without limitation holiday, vacation, and long- and short-term
                 disability). In the event that the Executive's participation in
                 any such employee benefit plan or program is barred, Yellow
                 shall arrange to provide the Executive with substantially
                 similar benefits. Any medical insurance coverage for such
                 two-year period pursuant to this subsection (f) shall become
                 secondary upon the earlier of (i)

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                 the date on which the Executive begins to be covered by
                 comparable medical coverage provided by a new employer, or (ii)
                 the earliest date upon which the Executive becomes eligible for
                 Medicare or a comparable Government insurance program.

             (g) All outstanding stock options held by the Executive at the time
                 of termination of his employment shall become fully exercisable
                 upon such termination of employment and may be exercised for
                 the balance of the term of such option.

             (h) If any payment or benefit received by or in respect of the
                 Executive under this Agreement or any other plan, arrangement
                 or agreement with Yellow (determined without regard to any
                 additional payments required under this subsection (h) and
                 Appendix B of this Agreement) (a "Payment") would be subject to
                 the excise tax imposed by Section 4999 of the Internal Revenue
                 Code of 1986, as amended (the "Code") (or any similar tax that
                 may hereafter be imposed) or any interest or penalties are
                 incurred by the Executive with respect to such excise tax (such
                 excise tax, together with any such interest and penalties,
                 being hereinafter collectively referred to as the "Excise
                 Tax"), Yellow shall pay to the Executive with respect to such
                 Payment at the time specified in Appendix B an additional
                 amount (the "Gross-up Payment") such that the net amount
                 retained by the Executive from the Payment and the Gross-up
                 Payment, after reduction for any Excise Tax upon the payment
                 and any federal, state and local

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                 income and employment tax and Excise Tax upon the Gross-up
                 Payment, shall be equal to the Payment. The calculation and
                 payment of the Gross-up Payment shall be subject to the
                 provisions of Appendix B.

         9.  Termination as a Result of a Corporate Restructuring. In the event
             that Executive's employment with Yellow is terminated as a result
             of a corporate restructuring which results in Executive performing
             essentially the same or greater duties that he currently performs
             for Yellow at essentially the same or greater level of compensation
             and benefits provided for under this Agreement for an entity that
             is no longer owned by Yellow, then Yellow and Executive shall
             negotiate, in good faith, a Transition Agreement documenting which
             payments and benefits provided for under this Agreement will be
             owing to Executive following a termination as a result of a
             corporate restructuring. Said Transition Agreement shall provide,
             at a minimum, that Executive shall be eligible for payments under
             the Pension Plan and for the supplemental retirement benefit
             provided for in Section 4(d) upon the effective date of a
             termination as a result of a corporate restructuring with actual
             payments under the Supplemental Retirement Benefit and the Pension
             Plan to be payable at the time and in the manner set forth in
             Section 4(d).

         10. Termination or Resignation Following a Change of Control. In the
             event that Executive resigns his employment with Yellow or suffers
             a "Termination" of such employment within two years after a "Change
             of Control" of Yellow under the circumstances described and the
             definitions

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             set forth in paragraphs 3 and 1 (c) of the Executive Severance
             Agreement entered into between Executive and Yellow on October 20,
             1998, the provisions of which are hereby incorporated by reference,
             the Executive shall be entitled to the greater of each benefit
             described in Section 8 or each benefit provided for under the
             Executive Severance Agreement.

         11. Entitlement To Other Benefits. Except as provided in this
             Agreement, this Agreement shall not be construed as limiting in any
             way any rights to benefits that the Executive may have pursuant to
             any other plan or program of Yellow.

         12. Arbitration.

             (a) Arbitration of Disputes. Any dispute between the parties hereto
                 arising out of, in connection with, or relating to this
                 Agreement or the breach thereof shall be settled by arbitration
                 in Overland Park, Kansas, in accordance with the rules then in
                 effect of the American Arbitration Association ("AAA").
                 Arbitration shall be the exclusive remedy for any such dispute
                 except only as to failure to abide by an arbitration award
                 rendered hereunder. Regardless of whether or not both parties
                 hereto participate in the arbitration proceeding, any
                 arbitration award rendered hereunder shall be final and binding
                 on each party hereto and judgment upon the award rendered may
                 be entered in any court having jurisdiction thereof.

                 The party seeking arbitration shall notify the other party in
                 writing and request the AAA to submit a list of 5 or 7
                 potential arbitrators.

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                 In the event the parties do not agree upon an arbitrator, each
                 party shall, in turn, strike one arbitrator from the list,
                 Yellow having the first strike, until only one arbitrator
                 remains, who shall arbitrate the dispute. The parties shall
                 have the opportunity to conduct reasonable discovery as
                 determined by the arbitrator, and the arbitration hearing shall
                 be conducted within 30 to 60 days of the selection of an
                 arbitrator or at the earliest date thereafter that the
                 arbitrator is available or as otherwise set by the arbitrator.

             b.  Indemnification. If arbitration occurs as provided for herein
                 and the Executive is awarded more than Yellow has asserted is
                 due him or otherwise substantially prevails therein, Yellow
                 shall reimburse the Executive for his reasonable attorneys'
                 fees, costs and disbursements incurred in such arbitration and
                 hereby agrees to pay interest on any money award obtained by
                 the Executive from the date payment should have been made until
                 the date payment is made, calculated at the prime interest rate
                 of Bank of America, Inc., Kansas City, Missouri in effect from
                 time to time from the date that payment(s) to him should have
                 been made under this Agreement. If the Executive enforces the
                 arbitration award in court, Yellow shall reimburse the
                 Executive for his reasonable attorneys' fees, costs and
                 disbursements incurred in such enforcement.

         13. Confidential Information. The Executive shall retain in confidence
             any confidential information known to him concerning Yellow and its

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             subsidiaries, and their respective businesses until such
             information is publicly disclosed. This provision shall survive the
             termination of the Executive's employment for any reason under this
             Agreement.

         14. Indemnification under Bylaws. Yellow shall provide the Executive
             with rights to indemnification by Yellow that are no less favorable
             to the Executive than those set forth in Yellow's by-laws as in
             effect as of the Effective Date.

         15. Successors. This Agreement shall be binding upon and inure to the
             benefit of the Executive and his estate and Yellow and any
             successor of Yellow, but neither this Agreement nor any rights
             arising hereunder may be assigned or pledged by the Executive.

         16. Severability. Any provision in this Agreement which is prohibited
             or unenforceable in any jurisdiction shall, as to such
             jurisdiction, be ineffective only to the extent of such prohibition
             or unenforceability without invalidating or affecting the remaining
             provisions hereof, and any such prohibition or unenforceability in
             any jurisdiction shall not invalidate or render unenforceable such
             provision in any other jurisdiction.

         17. Notices. All notices required or permitted to be given under this
             Agreement shall be given in writing and shall be deemed
             sufficiently given if delivered by hand or mailed by registered
             mail, return receipt requested, to his residence in the case of the
             Executive and to its principal executive offices in the case of
             Yellow. Either party may by giving written notice to the other
             party in accordance with this Section 15 change the address at
             which it is to receive notices hereunder.

         18. Controlling Law. This Agreement shall in all respects by governed
             by and construed in accordance with the laws of the State of
             Kansas.

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         19. Changes to Agreement. This Agreement may not be changed orally but
             only in a writing, signed by the party against whom enforcement is
             sought.

         20. Counterparts. This Agreement may be executed in any number of
             counterparts, each of which when so executed shall be deemed an
             original but all of which together shall constitute one and the
             same instrument.

         IN WITNESS WHEREOF, the parties have executed this Agreement on the
20th of April, 2000.

EXECUTIVE:                                       YELLOW CORPORATION

/s/  H. A. Trucksess, III                   By:  /s/  William F. Martin
------------------------------                 ---------------------------------

                                                 ATTEST

                                            By:  /s/  Lawrence D. Berkowitz
                                               ---------------------------------

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                                   Appendix A
                        Supplemental Retirement Benefits

         The following provisions shall be applicable with respect to the
supplemental retirement benefits described in Section 4(D) of this Agreement.

1.       Benefit Calculation

         For purposes of calculating the supplemental retirement benefits, the
         following assumptions shall be utilized.

         (a) "Credited Service", shall be assumed to be sixteen (16) years plus
             Executive's actual credited service credited under the Pension Plan
             from June 1, 1994.

         (b) Any vested accrued benefit which the Executive is paid under the
             Pension Plan, shall reduce any supplement retirement benefits
             payable under this Agreement; and

         (c) The defined terms used in this Appendix A and in Section 4(e) of
             this Agreement shall have the meanings provided in the Yellow
             Freight Office, Clerical, Sales and Supervisory Personnel Pension
             Plan as restated as of January 1, 1989 and as amended by Amendment
             No. 1 dated July 15, 1992, by Amendment No. 2 dated December 28,
             1994, all as in existence as of the Effective Date of this
             Agreement (collectively the "Pension Plan") unless another meaning
             is expressly provided in this Agreement and Appendix or unless the
             Executive and Yellow agree in writing to apply any subsequent
             amendments, revisions, interpretations or restatements of the
             Pension Plan.

2.       Taxability of Benefit

         The Executive and Yellow understand and agree that for federal tax
         purposes, all supplemental retirement benefits paid under this
         agreement to the Executive or his spouse shall be treated as ordinary
         income under the applicable provisions of the Internal Revenue Code of
         1986, as amended, and are subject to any taxes required to be withheld
         by federal, state or local law; provided that the Executive shall have
         the right to determine the timing of any withholding within the
         parameters permitted under the Code and under any Regulations or
         proposed Regulations under Code Section 3121(v) or any successor
         thereto.

3.       Nonassignability

         The supplemental retirement benefits payable under this Agreement, and
         any and all rights thereto, shall not be subject in any manner to
         anticipation, alienation, sale, transfer, assignment, pledge,
         encumbrance, charge,

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         garnishment, execution, or levy of any kind, either voluntarily or
         involuntarily. Any attempt to anticipate, alienate, sell, transfer,
         assign, pledge, encumber, charge, or otherwise dispose of any rights to
         benefits payable hereunder shall be void.

                                       21<PAGE>   1
                                                               Execution Version

                                                                     EXHIBIT 4.1

--------------------------------------------------------------------------------

                               NATG HOLDINGS, LLC

                                       and

                              ORIUS CAPITAL CORP.,

                                   as Issuers,

                                   ORIUS CORP.

                                       and

                       the other GUARANTORS named herein,

                                 as Guarantors,

                                       and

                    UNITED STATES TRUST COMPANY OF NEW YORK,

                                   as Trustee

                               ------------------

                                    INDENTURE

                          Dated as of February 9, 2000

                               ------------------

                   12 3/4% Senior Subordinated Notes due 2010

--------------------------------------------------------------------------------

<PAGE>   2
                                                               Execution Version

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                              CROSS-REFERENCE TABLE
                              ---------------------
<TABLE>
<CAPTION>

                    TIA                                 Indenture
                  Section                                Section
                  -------                                -------

<S>                                                    <C>
                  310(a)(1)                               7.10
                  310(a)(2)                               7.10
                  310(a)(3)                               N.A.
                  310(a)(4)                               N.A.
                  310(a)(5)                               7.8; 7.10
                  310(b)                                  7.8; 7.10; 13.2
                  310(c)                                  N.A.
                  311(a)                                  7.11
                  311(b)                                  7.11
                  311(c)                                  N.A.
                  312(a)                                  2.5
                  312(b)                                  13.3
                  312(c)                                  13.3
                  313(a)                                  7.6
                  313(b)(1)                               7.6
                  313(b)(2)                               7.6
                  313(c)                                  7.6; 13.2
                  313(d)                                  7.6
                  314(a)                                  4.8; 4.10; 13.2
                  314(b)                                  N.A.
                  314(c)(1)                               7.2; 13.4; 13.5
                  314(c)(2)                               7.2; 13.4; 13.5
                  314(c)(3)                               N.A.
                  314(d)                                  N.A.
                  314(e)                                  13.5
                  314(f)                                  N.A.
                  315(a)                                  7.1(b)
                  315(b)                                  7.5
                  315(c)                                  7.1
                  315(d)                                  6.5; 7.1(c)
                  315(e)                                  6.11
                  316(a)(last sentence)                   2.9
                  316(a)(1)(A)                            6.5
                  316(a)(1)(B)                            6.4
                  316(a)(2)                               9.5
                  316(b)                                  6.7
                  316(c)                                  9.5
                  317(a)(1)                               6.8
                  317(a)(2)                               6.9

</TABLE>

<PAGE>   4

<TABLE>

<S>                                                      <C>
                  317(b)                                  2.4
                  318(a)                                  13.1
                  318(c)                                  13.1
</TABLE>

----------------------

N.A. means Not Applicable

Note: This Cross-Reference Table shall not, for any purpose, be deemed to be a
part of the Indenture.

<PAGE>   5

         INDENTURE dated as of February 9, 2000 among NATG HOLDINGS, LLC, a
Delaware limited liability company ("NATG"), and ORIUS CAPITAL CORP., a Delaware
corporation (the "Corporate Issuer" and, together with NATG, the "Issuers"), as
Issuers, ORIUS CORP., a Florida corporation ("Parent"), and each of the other
Guarantors named herein, as Guarantors, and UNITED STATES TRUST COMPANY OF NEW
YORK, a banking corporation and trust company organized and existing under the
laws of the State of New York, in its capacity as Trustee (the "Trustee").

         The Issuers have duly authorized the creation of an issue of 12 3/4%
Senior Subordinated Notes due 2010 and, to provide therefor, the Issuers have
duly authorized the execution and delivery of this Indenture. All things
necessary to make the Securities, when duly issued and executed by the Issuers
and authenticated and delivered hereunder, the valid and binding obligations of
the Issuers and to make this Indenture a valid and binding agreement of the
Issuers have been done.

         Each party hereto agrees as follows for the benefit of each other party
and for the equal and ratable benefit of the Holders of the Securities:

                                   ARTICLE ONE

                   DEFINITIONS AND INCORPORATION BY REFERENCE

         Section 1.1  Definitions.

         "Acquired Indebtedness" means Indebtedness of a Person or any of its
Restricted Subsidiaries existing at the time such Person becomes a Restricted
Subsidiary of NATG or at the time it merges or consolidates with or into NATG or
any of its Restricted Subsidiaries or is assumed in connection with the
acquisition of assets from such Person and in each case whether or not incurred
by such Person in connection with, or in anticipation or contemplation of, such
Person becoming a Restricted Subsidiary of NATG or such acquisition, merger or
consolidation.

         "Acquisition Loans" means all Acquisition Loans under and as defined in
the Senior Secured Credit Agreement as in effect on the Issue Date.

         "Affiliate" means, as applied to any Person, any other Person directly
or indirectly controlling, controlled by, or under common control with, that
Person. For the purposes of this definition, "control" (including, with
correlative meanings, the terms "controlling", "controlled by" and "under common
control with"), as applied to any Person, means the possession, directly or
indirectly, of the power to direct or cause the direction of the management and
policies of that Person, whether through the ownership of voting securities or
by contract or otherwise. Notwithstanding the foregoing for purposes of Section
4.12, any Person who owns more than 10% of voting equity of a second Person or
who is an officer or director of such second Person shall be an Affiliate of
such second Person.

         "Affiliate Transaction" has the meaning set forth in Section 4.12.

<PAGE>   6

         "Agent" means any Registrar, Paying Agent or co-Registrar.

         "Asset Acquisition" means (a) an Investment by NATG or any of its
Restricted Subsidiaries in any other Person pursuant to which such Person shall
become a Restricted Subsidiary of NATG or shall be merged with or into NATG or
any Restricted Subsidiary of NATG or (b) the acquisition by NATG or any
Restricted Subsidiary of NATG of the assets of any person (other than a
Restricted Subsidiary of NATG) not in the ordinary course of business.

         "Asset Sale" means any direct or indirect sale, issuance, conveyance
transfer, lease (other than operating leases entered into in the ordinary course
of business), assignment or other transfer for value by Parent or any Restricted
Subsidiary of NATG to any Person other than NATG or any Wholly Owned Restricted
Subsidiary of NATG of (a) any Capital Stock of any Restricted Subsidiary of
NATG, or (b) any other property or assets of NATG or any Restricted Subsidiary
of NATG other than in the ordinary course of business; provided, that Asset
Sales shall not include: (i) a transaction or series of related transactions for
which NATG or any Restricted Subsidiary of NATG receives aggregate consideration
of less than $1,000,000, (ii) the sale, lease, conveyance, disposition or other
transfer of all or substantially all of the assets of NATG as permitted under
Section 5.1, (iii) any sale or other disposition of obsolete assets no longer
used or useful in the business of NATG or any of its Restricted Subsidiaries,
(iv) a disposition consisting of the making of a Permitted Investment, the
making of a Restricted Payment permitted under Section 4.3 or the liquidation of
Cash Equivalents, (v) the leasing or licensing of real or personal property
(including intellectual property) in the ordinary course of business for periods
not in excess of one year (subject to automatic renewals), (vi) the issuance of
Capital Stock by a Restricted Subsidiary of NATG to NATG or a Wholly Owned
Restricted Subsidiary of NATG, (vii) sales of accounts receivable and related
assets of the type specified in the definition of "Qualified Receivables
Transaction" to a Receivables Entity for cash or Purchase Money Notes in an
amount equal to the fair market value thereof, (viii) transfers of accounts
receivable and related assets of the type specified in the definition of
"Qualified Receivables Transaction" (or a fractional undivided interest therein)
by a Receivables Entity in a Qualified Receivables Transaction, and (ix) the
cancellation of promissory notes issued to Parent as permitted under Section
4.12(b)(ix).

         "Bankruptcy Law" means title 11 of the United States Code or any
similar Federal, state or foreign law for the relief of debtors.

         "Board of Directors" means, as to any Person, the board of directors of
such Person or any duly authorized committee thereof or, in the case of a Person
that is not a corporation, the analogous governing body of such Person.

         "Board Resolution" means, with respect to any Person, a copy of a
resolution certified by the Secretary or an Assistant Secretary of such Person
to have been duly adopted by the Board of Directors of such Person and to be in
full force and effect on the date of such certification, and delivered to the
Trustee.

         "Business Day" means any day other than a Saturday, Sunday or any other
day on which banking institutions in The City of New York are required or
authorized by law or other governmental action to be closed.

                                      -2-

<PAGE>   7

         "Capital Stock" means (i) with respect to any Person that is a
corporation, any and all shares, interests, participations or other equivalents
(however designated and whether or not voting) of corporate stock, including
each class of common stock and preferred stock of such Person and including any
warrants, options or rights to acquire any of the foregoing and instruments
convertible into any of the foregoing, and (ii) with respect to any Person that
is not a corporation, any and all partnership, membership or other equity
interests of such Person.

         "Capitalized Lease Obligation" means, as to any Person, the obligations
of such Person under a lease that are required to be classified and accounted
for as capital lease obligations under GAAP and, for purposes of this
definition, the amount of such obligations at any date shall be the capitalized
amount of such obligations at such date, determined in accordance with GAAP.

         "Cash Equivalents" means (i) any evidence of indebtedness, maturing not
more than one year after the date of issue, issued by the United States of
America or any instrumentality or agency thereof, the principal, interest and
premium, if any, of which is guaranteed fully by, or backed by the full faith
and credit of, the United States of America, (ii) dollar denominated time
deposits, certificates of deposit and bankers acceptances maturing not more than
one year after the date of purchase, issued by (x) any lender under the Senior
Secured Credit Agreement, (y) a commercial banking institution having, or which
is the principal banking subsidiary of a bank holding company having, combined
capital and surplus and undivided profits of not less than $200.0 million and a
commercial paper rating of "P-1" (or higher) according to Moody's, "A-1" (or
higher) according to S&P or the equivalent rating by any other nationally
recognized rating agency (any such bank, an "Approved Bank") or (z) a non-United
States commercial banking institution which is either currently ranked among the
100 largest banks in the world (by assets, according to the American Banker),
has combined capital and surplus and undivided profits of not less than $500.0
million or whose commercial paper (or the commercial paper of such bank's
holding company) has a rating of "P-1" (or higher) according to Moody's, "A-1"
(or higher) according to S&P or the equivalent rating by any other nationally
recognized rating agency, (iii) commercial paper, maturing not more than 270
days after the date of purchase, issued or guaranteed by a corporation (other
than Parent or any Subsidiary of Parent or any of their respective Affiliates)
organized and existing under the laws of any state within the United States of
America with a rating, at the time as of which any determination thereof is to
be made, of "P-1" (or higher) according to Moody's or "A-1" (or higher)
according to S&P, (iv) demand deposits with any bank or trust company maintained
in the ordinary course of business, (v) repurchase or reverse repurchase
agreements covering obligations of the type specified in clause (i) with a term
of not more than seven days with any Approved Bank, and (vi) shares of any money
market mutual fund rated at least AAA or the equivalent thereof by S&P or at
least AAA or the equivalent thereof by Moody's.

         "Change of Control" means: (i) any sale, lease or transfer of all or
substantially all of the assets of NATG and its Restricted Subsidiaries, taken
as a whole, to any Person or group (as such term is used in Section 13(d)(3) of
the Exchange Act), (ii) the liquidation or dissolution of Parent or any Issuer,
(iii) prior to a Qualified IPO, (A) WSP and its Affiliates cease to beneficially
own (and have the exclusive power to vote with respect to), directly or
indirectly, at least 35% of the outstanding Voting Securities of Parent entitled
(without regard to the occurrence of any contingency) to vote (including,
without limitation, pursuant to any valid and enforceable

                                      -3-

<PAGE>   8

stockholders or other voting agreement) for the election of a majority of the
members of the Board of Directors of Parent, and in any event sufficient to
direct or cause the direction of the management and policies of Parent, (B) any
Person or group (as such term is used in Section 13(d)(3) of the Exchange Act)
(other than WSP and its Affiliates or a Permitted Group) shall become the owner,
directly or indirectly, beneficially or of record, of a greater number of the
Voting Securities of Parent than the number of Voting Securities of Parent then
owned beneficially and of record by WSP and its Affiliates or (C) the nominees
of WSP and its Affiliates shall at any time fail or cease to constitute a
majority of the members of the Board of Directors of Parent, (iv) after a
Qualified IPO, (A) (1) any Person or group (as such term is used in Section
13(d)(3) of the Exchange Act) (other than WSP and its Affiliates or a Permitted
Group) shall at any time become the owner, directly or indirectly, beneficially
or of record, of shares representing more than 35% of the outstanding Voting
Securities of Parent and (2) the percentage of Voting Securities beneficially
owned by WSP and its Affiliates is less than the percentage so owned or acquired
by such Person or group, or (B) the replacement of a majority of the directors
on the Board of Directors of Parent over a two-year period from the directors
who constituted the Board of Directors of Parent at the beginning of such
period, and such replacement shall not have been approved by a vote of at least
a majority of the Board of Directors of Parent then still in office who either
were members of such Board of Directors at the beginning of such period or whose
election as a member of such Board of Directors was previously so approved, or
(v) Parent ceases to beneficially own (and have the exclusive power to vote with
respect to) all of the issued and outstanding Capital Stock of NATG free and
clear of all Liens other than Liens arising under the Senior Secured Credit
Agreement.

         "Change of Control Date" has the meaning set forth in Section 4.15.

         "Change of Control Offer" has the meaning set forth in Section 4.15.

         "Change of Control Payment Date" has the meaning set forth in Section
4.15.

         "Commission" means the Securities and Exchange Commission.

         "Common Stock" of any Person means any and all shares, interests or
other participations in, and other equivalents (however designated and whether
voting or non-voting) of such Person's common stock, whether outstanding on the
Issue Date or issued after the Issue Date, and includes, without limitation, all
series and classes of such common stock.

         "Consolidated EBITDA" means, for any period for any Person, the sum,
without duplication, of the amounts for such period of (i) Consolidated Net
Income, (ii) Consolidated Interest Expense, (iii) provisions for taxes based on
income, (iv) total depreciation expense, (v) total amortization expense, and
(vi) other non-cash items reducing Consolidated Net Income, less other non-cash
items increasing Consolidated Net Income other than the accrual of revenue in
the ordinary course of business, all of the foregoing as determined on a
consolidated basis for such Person and its Subsidiaries in conformity with GAAP.

         "Consolidated Fixed Charge Coverage Ratio" shall mean the ratio of
Consolidated EBITDA of NATG during the four full fiscal quarters for which
internal financial statements are available (the "Four Quarter Period") ending
on or prior to the date of the transaction giving rise to

                                      -4-

<PAGE>   9

the need to calculate the Consolidated Fixed Charge Coverage Ratio (the
"Transaction Date") to Consolidated Fixed Charges of NATG for such Four Quarter
Period. In addition to, and without limitation of, the foregoing, for purposes
of this definition, "Consolidated EBITDA" and "Consolidated Fixed Charges" shall
be calculated after giving effect on a pro forma basis for the period of such
calculation to (i) the Incurrence or repayment of any Indebtedness of NATG or
any of its Restricted Subsidiaries (and the application of the proceeds thereof)
giving rise to the need to make such calculation and any Incurrence or repayment
of other Indebtedness (and the application of the proceeds thereof), other than
the Incurrence or repayment of Indebtedness in the ordinary course of business
for working capital purposes pursuant to working capital facilities (including
revolving credit facilities), occurring during the Four Quarter Period or at any
time subsequent to the last day of the Four Quarter Period and on or prior to
the Transaction Date, as if such Incurrence or repayment, as the case may be
(and the application of the proceeds thereof), occurred on the first day of the
Four Quarter Period and (ii) any Asset Sales or other dispositions or Asset
Acquisitions (including, without limitation, any Asset Acquisition giving rise
to the need to make such calculation as a result of NATG or one of its
Restricted Subsidiaries (including any Person who becomes a Restricted
Subsidiary as a result of the Asset Acquisition) Incurring Indebtedness and also
including any Consolidated EBITDA (provided, that such Consolidated EBITDA shall
be included only to the extent includable pursuant to the definition of
"Consolidated Net Income" or to the extent it is excluded pursuant to clause
(ii) of the definition of "Consolidated Net Income") and shall be calculated on
a pro forma basis with respect to any Asset Acquisition taking into account the
Pro Forma Adjustments, if any, resulting from such Asset Acquisitions)
attributable to the assets which are the subject of the Asset Acquisition or
Asset Sale during the Four Quarter Period or at any time subsequent thereto)
occurring during the Four Quarter Period or at any time subsequent to the last
day of the Four Quarter Period and on or prior to the Transaction Date, as if
such Asset Sale or other disposition or Asset Acquisition (including any related
Incurrence of Indebtedness) occurred on the first day of the Four Quarter
Period. If NATG or any of its Restricted Subsidiaries directly or indirectly
guarantees Indebtedness of a third Person, the preceding sentence shall give
effect to the Incurrence of such guaranteed Indebtedness as if NATG or such
Restricted Subsidiary had directly incurred or otherwise assumed such guaranteed
Indebtedness (calculated to avoid duplication). Furthermore, in calculating
"Consolidated Fixed Charges" for purposes of determining the denominator (but
not the numerator) of this "Consolidated Fixed Charge Coverage Ratio," (1)
interest on outstanding Indebtedness determined on a fluctuating basis as of the
Transaction Date and which will continue to be so determined thereafter shall be
deemed to have accrued at a fixed rate per annum equal to the rate of interest
on such Indebtedness in effect on the Transaction Date, (2) if interest on any
Indebtedness actually incurred on the Transaction Date may optionally be
determined at an interest rate based upon a factor of a prime or similar rate, a
eurocurrency interbank offered rate, or other rates, then the interest rate in
effect on the Transaction Date will be deemed to have been in effect during the
Four Quarter Period, and (3) notwithstanding clause (1) above, interest on
Indebtedness determined on a fluctuating basis, to the extent such interest is
covered by Interest Rate Agreements relating thereto, shall be deemed to accrue
at the rate per annum resulting after giving effect to the operation of such
agreements.

         "Consolidated Fixed Charges" shall mean, with respect to any Person for
any period, the sum, without duplication, of (i) Consolidated Interest Expense
(before amortization or write-off of

                                      -5-

<PAGE>   10

debt issuance costs associated with the offering of the Securities on the Issue
Date), plus (ii) to the extent not included in Consolidated Interest Expense,
the product of (x) the amount of all dividend payments on any series of Capital
Sock of such Person (other than dividends paid in Qualified Capital Stock) paid
in cash during such period, times (y) a fraction, the numerator of which is one
and the denominator of which is one minus the then current effective
consolidated federal, state and local tax rate of such Person, expressed as a
decimal.

         "Consolidated Interest Expense" shall mean, with respect to any Person
for any period, the sum of, without duplication: (i) the aggregate of the
interest expense of such Person and its Restricted Subsidiaries for such period
determined on a consolidated basis in accordance with GAAP, including without
limitation, (a) any amortization of debt discount and amortization or write-off
of deferred financing costs, (b) the net costs under Interest Rate Agreements,
(c) all capitalized interest and (d) the interest portion of any deferred
payment obligation; and (ii) the interest component of Capitalized Lease
Obligations paid, accrued and/or scheduled to be paid or accrued by such Person
and its Restricted Subsidiaries during such period as determined on a
consolidated basis in accordance with GAAP.

         "Consolidated Net Income" shall mean, for any period for any Person,
the net income (or loss) of such Person and its Restricted Subsidiaries on a
consolidated basis for such period taken as a single accounting period
determined in conformity with GAAP; provided, that there shall be excluded (i)
the income (or loss) of any Person (other than a Restricted Subsidiary of such
Person) in which any other Person (other than such first Person or any of its
Restricted Subsidiaries) has a joint interest, except to the extent of the
amount of dividends or other distributions actually paid to such Person or any
of its Restricted Subsidiaries by such second Person during such period, (ii)
the income (or loss) of any other Person accrued prior to the date it becomes a
Restricted Subsidiary of such first Person or is merged into or consolidated
with such first Person or any of its Restricted Subsidiaries or whose assets are
acquired by such first Person or any of its Restricted Subsidiaries, (iii) the
income of any Subsidiary of such first Person to the extent that the declaration
or payment of dividends or similar distributions by that Restricted Subsidiary
of that income is not at the time permitted by operation of the terms of its
charter or any agreement, instrument, judgment, decree, order, statute, rule or
governmental regulation applicable to that Restricted Subsidiary, (iv) any
after-tax gains or losses attributable to Asset Sales (without regard to the
$1.0 million limitation set forth in the definition thereof), and (v) (to the
extent not included in clauses (i) through (iv) above) any net non-cash
extraordinary gains or net noncash extraordinary losses. For purposes of
computing Consolidated Net Income there shall be excluded from the computation
thereof, without duplication and to the extent not otherwise excluded from the
computation thereof, (i) non-recurring fees and expenses incurred in connection
with the consummation of the LISN Acquisition in an aggregate amount not to
exceed $16.0 million and (ii) non-recurring fees and expenses incurred in
connection with the issuance of the Securities on the Issue Date in an aggregate
amount not to exceed $7.0 million. For purposes of computing Consolidated Net
Income, but only to the extent used in determining the Consolidated Fixed Charge
Coverage Ratio, there shall be excluded from the computation thereof, without
duplication and to the extent not otherwise excluded from the computation
thereof non-recurring fees and expenses incurred in connection with the
consummation of any Asset Acquisition in an aggregate amount not to exceed 5% of
the total consideration for such Asset Acquisition.

                                      -6-

<PAGE>   11

         "Contingent Obligations" means as to any Person, any obligation of such
Person guaranteeing or intending to guarantee any Indebtedness, leases,
dividends or other obligations ("primary obligations") of any other Person (the
"primary obligor") in any manner, whether directly or indirectly, including,
without limitation, any obligation of such Person, whether or not contingent,
(i) to purchase any such primary obligation or any property constituting direct
or indirect security therefor, (ii) to advance or supply funds (a) for the
purchase or payment of any such primary obligation or (b) to maintain working
capital or equity capital of the primary obligor or otherwise to maintain the
net worth or solvency of the primary obligor, (iii) to purchase property,
securities or services primarily for the purpose of assuring the owner of any
such primary obligation of the ability of the primary obligor to make payment of
such primary obligation or (iv) otherwise to assure or hold harmless the owner
of such primary obligation against loss in respect thereof; provided, that the
term "Contingent Obligation" shall not include endorsements of instruments for
deposit or collection in the ordinary course of business. The amount of any
Contingent Obligation shall be deemed to be an amount equal to the stated or
determinable amount of the primary obligation in respect of which such
Contingent Obligation is made or, if not stated or determinable, the maximum
reasonably anticipated liability in respect thereof (assuming such Person is
required to perform thereunder) as determined by such Person in good faith.

         "Corporate Issuer" means Orius Capital Corp., a Delaware corporation.

         "Covenant Defeasance" has the meaning set forth in Section 8.2.

         "Currency Agreement" means any foreign exchange contract, currency swap
agreement, futures contract, option contract, synthetic cap or other similar
agreement or arrangement designed to protect NATG or any of its Restricted
Subsidiaries against fluctuations in currency values.

         "Custodian" any receiver, interim receiver, receiver and manager,
trustee, assignee, liquidator, sequestrator or similar official charged with
maintaining possession or control over property for one or more creditors,
whether under any Bankruptcy Law or otherwise.

         "Default" means an event or condition the occurrence of which is, or
with the lapse of time or the giving of notice or both would be, an Event of
Default.

         "Depository" shall mean The Depository Trust Company, New York, New
York, or a successor thereto registered under the Exchange Act or other
applicable statute or regulation.

         "Designated Senior Debt" means (i) Indebtedness under or in respect of
the Senior Secured Credit Agreement and (ii) any other Indebtedness constituting
both Senior Debt and Guarantor Senior Debt which, at the time of determination,
has an aggregate principal amount of at least $25.0 million and is specifically
designated in the instrument evidencing such Senior Debt as "Designated Senior
Debt" by the Issuers.

         "Disqualified Capital Stock" means that portion of any Capital Stock
which, by its terms (or by the terms of any security into which it is
convertible or for which it is exchangeable), or upon the happening of any
event, matures or is mandatorily redeemable, pursuant to a sinking fund
obligation or otherwise, or is redeemable at the sole option of the holder
thereof on or prior to the

                                      -7-

<PAGE>   12

Maturity Date. Notwithstanding the preceding sentence, any Capital Stock that
would constitute Disqualified Capital Stock solely because the holder thereof
has the right to require the repurchase of such Capital Stock upon the
occurrence of a change of control or an asset sale (each such term being defined
in substantially the same manner as the corresponding terms in this Indenture)
shall not constitute Disqualified Capital Stock if the terms of such Capital
Stock provide that such Capital Stock may not be repurchased or redeemed
pursuant to such provisions unless the Issuers have first complied with their
obligations under Section 4.15 and Section 4.16 and that such repurchase or
redemption complies with Section 4.3.

         "Distribution Compliance Period" means, with respect to any Securities,
the period of 40 consecutive days beginning on and including the later of (i)
the day on which such Securities are first offered to Persons other than
distributors (as defined in Regulation S under the Securities Act) and (ii) the
date of issue of such Securities.

         "Documents" has the meaning ascribed to such term in the Senior Secured
Credit Agreement as in effect on the Issue Date.

         "Equity Offering" means a public or private offering of Qualified
Capital Stock (other than public offerings with respect to Parent's or an
Issuer's Common Stock on Form S-8 or any replacement form for such Form S-8) of
Parent or an Issuer.

         "Event of Default" has the meaning set forth in Section 6.1.

         "Exchange Act" means the Securities Exchange Act of 1934, as amended,
or any successor statute or statutes thereto.

         "Exchange Securities" means securities issued in exchange for the
Initial Securities pursuant to the terms of a Registration Rights Agreement.

         "Existing Debt" means the Indebtedness of NATG and its Restricted
Subsidiaries that is Incurred prior to, and is to remain outstanding after, the
issuance of the Securities on the Issue Date and the application of the proceeds
thereof; provided, that Existing Debt shall not include any obligations in
respect of the Senior Secured Credit Agreement.

         "GAAP" means generally accepted accounting principles set forth in the
opinions and pronouncements of the Accounting Principles Board of the American
Institute of Certified Public Accountants and statements and pronouncements of
the Financial Accounting Standards Board or in such other statements by such
other entity as may be approved by a significant segment of the accounting
profession of the United States, as in effect from time to time.

         "Global Security" shall mean one or more IAI Global Securities,
Regulation S Global Securities and 144A Global Securities.

         "Guarantee Obligations" has the meaning set forth in Section 12.1.

         "Guarantees" means the guarantees of the Securities by the Guarantors.

                                      -8-

<PAGE>   13

         "Guarantor" means (i) Parent, (ii) each Restricted Subsidiary of Parent
other than the Issuers and (iii) each Restricted Subsidiary of Parent that in
the future executes a supplemental indenture in which such Restricted Subsidiary
agrees to be bound by the terms of this Indenture as a Guarantor; provided, that
any Person constituting a Guarantor as described above shall cease to constitute
a Guarantor when its respective Guarantee is released in accordance with the
terms of this Indenture.

         "Guarantor Senior Debt" means with respect to any Guarantor, the
principal of, premium, if any, interest (including any interest accruing
subsequent to the filing of a petition of bankruptcy at the rate provided for in
the documentation with respect thereto, whether or not such interest is an
allowed claim under applicable law), fees, expenses, indemnities and other
amounts and obligations incurred or owing on any Indebtedness of a Guarantor,
whether outstanding on the Issue Date or thereafter created, incurred, assumed
or guaranteed, unless, in the case of any particular Indebtedness, the
instrument creating or evidencing the same or pursuant to which the same is
outstanding expressly provides that such Indebtedness shall not be senior in
right of payment to the Guarantee of such Guarantor. Without limiting the
generality of the foregoing, "Guarantor Senior Debt" shall also include the
principal of, premium, if any, interest (including any interest accruing
subsequent to the filing of a petition of bankruptcy at the rate provided for in
the documentation with respect thereto, whether or not such interest is an
allowed claim under applicable law) on, and all other amounts owing in respect
of, (x) all monetary obligations of every nature under the Senior Secured Credit
Agreement, including, without limitation, obligations to pay principal and
interest, reimbursement obligations under letters of credit, fees, expenses and
indemnities and (y) all IRA Obligations, in each case whether outstanding on the
Issue Date or thereafter incurred. Notwithstanding the foregoing, "Guarantor
Senior Debt" shall not include (i) any Indebtedness of such Guarantor to a
Subsidiary of such Guarantor, (ii) Indebtedness to, or guaranteed on behalf of,
any director, officer, employee of either of such Guarantor or any Subsidiary of
such Guarantor (including, without limitation, amounts owed for compensation),
(iii) Indebtedness to trade creditors and other amounts incurred in connection
with obtaining goods, materials or services, (iv) Indebtedness represented by
Disqualified Capital Stock, (v) any liability for federal, state, local or other
taxes owed or owing such Guarantor, (vi) Indebtedness to the extent incurred in
violation of Section 4.4, (vii) Indebtedness which, when incurred and without
respect to any election under Section 1111(b) of Title 11, United States Code,
is without recourse to such Guarantor, and (viii) any Indebtedness which is, by
its express terms, subordinated in right of payment to any other Indebtedness of
such Guarantor including, without limitation, in the case of Parent,
Indebtedness evidenced by the Junior Subordinated Notes.

         "Hedging Obligations" of any Person means any obligation of such Person
under (i) an Interest Rate Agreement, (ii) a Currency Agreement, and (iii) any
Synthetic Arrangement.

         "IAI Global Security" means a permanent global security in registered
form representing the aggregate principal amount of Securities from time to time
sold to Institutional Accredited Investors.

         "Incur" or "incur" means, with respect to any Indebtedness or other
obligation of any Person, to create, issue, incur (by conversion, exchange or
otherwise), assume (including by the

                                      -9-

<PAGE>   14

acquisition of assets subject to Indebtedness), guarantee or otherwise become
liable in respect of such Indebtedness or other obligation or the recording, as
required pursuant to GAAP or otherwise, of any such Indebtedness or other
obligation on the balance sheet of such Person (and "Incurrence," "Incurred,"
"Incurrable" an "Incurring" shall have meanings correlative to the foregoing);
provided, that (x) any amendment, modification or waiver of any document
pursuant to which Indebtedness was previously Incurred shall only be deemed to
be an Incurrence of Indebtedness if and to the extent such amendment,
modification or waiver (i) increases the principal thereof or interest rate or
premium payable thereon or (ii) changes to an earlier date the stated maturity
thereof or the date of any scheduled or required principal payment thereon or
the time or circumstances under which such Indebtedness shall be redeemed and
(y) any Indebtedness of a Person existing at the time such Person becomes (after
the Issue Date) a Restricted Subsidiary of NATG (whether by merger,
consolidation, acquisition or otherwise) shall be deemed to be Incurred by such
Restricted Subsidiary at the time it becomes a Restricted Subsidiary of NATG.

         "Indebtedness" of any Person shall mean, without duplication, (i) all
indebtedness of such Person for borrowed money, (ii) the deferred purchase price
of assets or services (including any earn-out obligations in connection with any
acquisition) which in accordance with GAAP would be shown on the liability side
of the balance sheet of such Person, (iii) the face amount of all letters of
credit issued for the account of such Person and, without duplication, all
unreimbursed drafts drawn thereunder, (iv) all indebtedness of a second Person
secured by any Lien on any property owned by such first Person (excluding
advances or prepayments made to any Borrower or any of their Subsidiaries
pursuant to turnkey agreements entered into in the ordinary course of business
with TCI or any of its Affiliates), whether or not such indebtedness has been
assumed, (v) all Capitalized Lease Obligations of such Person, (vi) all
obligations of such Person to pay a specified purchase price for goods or
services whether or not delivered or accepted, i.e., take-or-pay and similar
obligations, (vii) all Hedging Obligations of such Person, and (viii) all
Contingent Obligations of such Person (other than Contingent Obligations arising
from the guarantee by such Person of the obligations of Parent and/or its
Subsidiaries to the extent such guaranteed obligations do not constitute
Indebtedness and are otherwise permitted hereunder); provided, that Indebtedness
shall not include trade payables and accrued expenses, in each case arising in
the ordinary course of business.

         "Indenture" means this Indenture, as amended or supplemented from time
to time in accordance with the terms hereof.

         "Independent Financial Advisor" means an accounting, appraisal,
valuation or investment banking firm (i) which does not, and whose directors,
officers and employees or Affiliates do not, have a direct or indirect financial
interest in Parent or any of its Subsidiaries and (ii) which, in the judgment of
the Board of Directors of Parent, is otherwise independent and qualified to
perform the task for which it is to be engaged.

         "Initial Purchasers" means Deutsche Bank Securities, Inc. and Banc of
America Securities LLC.

                                      -10-

<PAGE>   15

         "Initial Securities" means the 12 3/4% Senior Subordinated Notes due
2010 of the Issuers issued on the Issue Date in accordance with the requirements
of Section 2.2 of this Indenture; provided, that the term Initial Securities
shall not include any Exchange Securities issued in exchange for theretofore
outstanding Initial Securities.

         "Institutional Accredited Investor" or "IAI" means an institution that
is an "accredited investor" as that term is defined in Rule 501(a)(1), (2), (3)
or (7) under the Securities Act.

         "Interest Payment Date" means the stated maturity of an installment of
interest on the Securities.

         "Interest Rate Agreement" means any interest rate swap agreement, any
interest rate cap agreement, any interest rate collar agreement or other similar
agreement or arrangement designed to protect Parent or any Restricted Subsidiary
of Parent against fluctuations in interest rates.

         "Investment" by any Person in any other Person means, with respect to
any Person, any direct or indirect loan or other extension of credit (including,
without limitation, a guarantee) or capital contribution to (by means of any
transfer of cash or other property to others or any payment for property or
services for the account or use of others), or any purchase, acquisition by such
Person of any Capital Stock, bonds, notes, debentures or other securities or
evidences of Indebtedness issued by, such other Person. "Investment" shall
exclude extensions of trade credit by the Issuers and their Restricted
Subsidiaries on commercially reasonable terms in accordance with their normal
trade practices and advances to employees for moving, entertainment and travel
expenses, drawing accounts and similar expenditures in the ordinary course of
business. For the purposes of Section 4.3,

                  (1) NATG shall be deemed to have made an "Investment" equal to
         the fair market value of the net assets of any Restricted Subsidiary of
         NATG at the time that such Restricted Subsidiary is designated an
         Unrestricted Subsidiary and the aggregate amount of Investments made
         subsequent to the Issue Date shall exclude (to the extent the
         designation as an Unrestricted Subsidiary was included as a Restricted
         Payment) the fair market value of the net assets of any Unrestricted
         Subsidiary at the time that such Unrestricted Subsidiary is designated
         a Restricted Subsidiary, not to exceed the amount of the Investment
         deemed made at the date of designation thereof as an Unrestricted
         Subsidiary, and

                  (2) the amount of any Investment shall be the original cost of
         such Investment plus the cost of all additional Investments by NATG or
         any of its Restricted Subsidiaries, without any adjustments for
         increases or decreases in value, or write-ups, writedowns or write-offs
         with respect to such Investment, reduced by the payment of dividends or
         distributions (including tax sharing payments) in connection with such
         Investment or any other amounts received in respect of such Investment;
         provided, that no such payment of dividends or distributions or receipt
         of any such other amounts shall reduce the amount of any Investment if
         such payment of dividends or distributions or receipt of any such
         amounts would be included in Consolidated Net Income. If NATG or any
         Restricted Subsidiary of NATG sells or otherwise disposes of any
         Capital Stock of any Restricted Subsidiary of NATG such that, after
         giving effect to any such sale or disposition, NATG no longer owns,

                                      -11-

<PAGE>   16

         directly or indirectly, more than 50% of the outstanding Common Stock
         of such Restricted Subsidiary, NATG shall be deemed to have made an
         Investment on the date of any such sale or disposition equal to the
         fair market value of the Capital Stock of such Restricted Subsidiary
         not sold or disposed of.

         "Investor Rights Agreement" means the Investor Rights Agreement, dated
December 15, 1999, between Parent and its stockholders entered into in
connection with the LISN Acquisition, as in effect on the Issue Date.

         "IRA Obligation" means the obligations of a Person under an Interest
Rate Agreement.

         "Issue Date" means February 9, 2000, the date of original issuance of
Initial Securities under this Indenture.

         "Issuers" means NATG and the Corporate Issuer, the issuers of the
Securities under this Indenture, until, in each case, a successor replaces it
pursuant to this Indenture and thereafter shall mean such successor entity.

         "Junior Subordinated Notes" means, collectively, (i) those certain
unsecured and unguaranteed 12% Subordinated Promissory Notes dated December 15,
1999 outstanding on the Issue Date (the "Initial Junior Subordinated Notes") and
(ii) additional junior subordinated promissory notes issued after the Issue Date
with terms substantially similar to those of the Initial Junior Subordinated
Notes.

         "Legal Defeasance" has the meaning set forth in Section 8.2.

         "Lien" means any lien, mortgage, pledge, assignment, security interest,
charge, hypothecation, preference, priority, privilege, lease or encumbrance of
any kind (including any conditional sale or other title retention agreement, any
lease in the nature thereof, and any agreement to give any security interest)
and any option, trust or other preferential arrangement having the practical
effect of any of the foregoing.

         "LISN Acquisition" means the series of transactions whereby Parent
acquired control of LISN Holdings and its subsidiaries.

         "LISN Holdings" means LISN Holdings, Inc., an Ohio corporation.

         "Maturity Date" means February 1, 2010, the final maturity date of the
Securities.

         "Moody's" means Moody's Investors Service, Inc.

         "NATG" means NATG Holdings, LLC, a Delaware limited liability company.

         "Net Cash Proceeds" means, with respect to any Asset Sale, the proceeds
in the form of cash or Cash Equivalents including payments in respect of
deferred payment obligations when received in the form of cash or Cash
Equivalents (other than the portion of any such deferred payment constituting
interest) received by Parent or any of its Restricted Subsidiaries from such

                                      -12-

<PAGE>   17

Asset Sale net of (i) reasonable out-of-pocket expenses and fees relating to
such Asset Sale (including, without limitation, legal, accounting and investment
banking fees and sales commissions), (ii) taxes paid or payable after taking
into account any reduction in consolidated tax liability due to available tax
credits or deductions and any tax sharing arrangements, (iii) any portion of any
such proceeds which Parent determines in good faith should be reserved for
post-closing adjustments (to the extent Parent delivers to the Trustee an
Officers' Certificate signed by the chief financial officer of Parent as to such
determination); provided, that on the day all such post-closing adjustments have
been determined (which shall not be later than six months following the date of
the respective Asset Sale), the amount (if any) by which the reserved amount in
respect of such sale or disposition exceeds the actual post-closing adjustments
payable by Parent or any of its Restricted Subsidiaries shall constitute Net
Cash Proceeds received by Parent or any such Restricted Subsidiaries on such
date, and (iv) repayment of Indebtedness that is required to be repaid in
connection with such Asset Sale.

         "Net Proceeds Offer" has the meaning set forth in Section 4.16.

         "Net Proceeds Offer Amount" has the meaning set forth in Section 4.16.

         "Net Proceeds Offer Payment Date" has the meaning set forth in Section
4.16.

         "Net Proceeds Offer Trigger Date" has the meaning set forth in Section
4.16.

         "Non-payment Default" has the meaning set forth in Section 10.2.

         "Non-Recourse Debt" means Indebtedness: (1) as to which neither NATG
nor any of its Restricted Subsidiaries (other than a Receivables Entity) (a)
provides credit support of any kind (including any undertaking, agreement or
instrument that would constitute Indebtedness), (b) is directly or indirectly
liable as a guarantor or otherwise, or (c) constitutes the lender; and (2) as to
which the lenders thereof have been notified in writing that they will not have
any recourse to the stock or assets of NATG or any of its Restricted
Subsidiaries (other than a Receivables Entity).

         "Non-U.S. Person" has the meaning assigned to such term in Regulation
S.

         "Officer" means, with respect to any Person, the Chairman of the Board,
the Chief Executive Officer, the President, any Vice President, the Chief
Financial Officer, the Controller, the Treasurer, the Secretary or the Assistant
Secretary of such Person.

         "Officers' Certificate" of a Person means a certificate signed by two
Officers of such Person.

         "144A Global Security" means a permanent global security in registered
form representing the aggregate principal amount of Securities from time to time
sold in reliance on Rule 144A under the Securities Act.

         "Opinion of Counsel" means a written opinion from legal counsel which
opinion and counsel are reasonably acceptable to the Trustee.

                                      -13-

<PAGE>   18

         "Parent" means Orius Corp., a Florida corporation, until a successor
replaces it pursuant to this Indenture, and thereafter shall mean such successor
entity.

         "Parent Common Stock" means the Common Stock of Parent.

         "Parent Preferred Stock" means the Series C Participating Preferred
Stock of Parent.

         "Participants" has the meaning set forth in Section 2.15.

         "Paying Agent" has the meaning set forth in Section 2.3.

         "Payment Blockage Notice" has the meaning set forth in Section 10.2.

         "Payment Blockage Period" has the meaning set forth in Section 10.2.

         "Payment Default" has the meaning set forth in Section 10.2.

         "Permitted Business" means the business of Parent and its Restricted
Subsidiaries as of the Issue Date and any business reasonably related,
complementary or ancillary thereto or a reasonable expansion thereof.

         "Permitted Group" means any group of investors deemed to be a person
(as defined in Section 13(d)(3) of the Exchange Act) by virtue of the Investor
Rights Agreement.

         "Permitted Indebtedness" means

                  (i) obligations under this Indenture, the Securities and the
         Guarantees,

                  (ii) Indebtedness incurred pursuant to the Senior Secured
         Credit Agreement in an aggregate principal amount at any time
         outstanding not to exceed $410.0 million, less the amount of all
         permanent prepayments of Senior Term Loans actually made and permanent
         reductions of commitments relating to Revolving Loans or Acquisition
         Loans and the termination of unused Rollover Letters of Credit
         availability,

                  (iii) Existing Debt,

                  (iv) IRA Obligations covering Indebtedness otherwise permitted
         by this Indenture to the extent the notional principal amount of such
         IRA Obligations does not exceed the principal amount of the
         Indebtedness to which such IRA Obligations relate,

                  (v) the Incurrence by NATG or any of its Restricted
         Subsidiaries of Hedging Obligations that are Incurred for the purpose
         of fixing or hedging the value of foreign currencies or the cost of
         commodities purchased or received by NATG or any of its Restricted
         Subsidiaries,

                  (vi) Permitted Refinancing Indebtedness,

                                      -14-

<PAGE>   19

                  (vii) Indebtedness of NATG or a Restricted Subsidiary of NATG
         to NATG or a Restricted Subsidiary of NATG; provided, that (y) if as of
         any date any Person other than NATG or a Restricted Subsidiary of NATG
         holds any such Indebtedness or holds a Lien in respect of such
         Indebtedness (other than a Lien in connection with the Senior Secured
         Credit Agreement), such date shall be deemed the Incurrence of
         Indebtedness not constituting Permitted Indebtedness by the issuer of
         such Indebtedness and (z) if an Issuer or Subsidiary Guarantor is the
         obligor on such Indebtedness, such Indebtedness shall constitute
         Subordinated Indebtedness,

                  (viii) Indebtedness arising from the honoring by a bank or
         other financial institution of a check, draft or similar instrument
         inadvertently drawn against insufficient funds in the ordinary course
         of business; provided, that such Indebtedness must be extinguished
         within five Business Days of Incurrence,

                  (ix) obligations in respect of workers' compensation claims,
         self-insurance obligations, performance, surety and other similar bonds
         and completion guarantees provided by NATG or a Restricted Subsidiary
         of NATG in the ordinary course of business in accordance with customary
         industry practice, in amount and for purposes customary in such
         Person's industry,

                  (x) Indebtedness arising from agreements of NATG or Restricted
         Subsidiary of NATG providing for indemnification, adjustment of
         purchase price, earn out or other similar obligations, in each case,
         incurred or assumed in connection with the disposition of any business,
         assets, or a Restricted Subsidiary of NATG, other than guarantees of
         Indebtedness incurred by any Person acquiring all or any portion of
         such business, assets or Restricted Subsidiary for the purpose of
         financing such acquisition; provided, that the maximum assumable
         liability in respect of all such Indebtedness shall at no time exceed
         the gross proceeds actually received by an Issuer or Subsidiary
         Guarantor in connection with such disposition,

                  (xi) Capitalized Lease Obligations, mortgage financings and
         Purchase Money Obligations of an Issuer or Subsidiary Guarantor
         incurred for the purpose of financing all or a part of the purchase
         price or cost of construction or improvement of property, plant or
         equipment used in the business of an Issuer or Subsidiary Guarantor,
         not to exceed $20.0 million at any one time outstanding,

                  (xii) guarantees by an Issuer or Subsidiary Guarantor of
         Indebtedness of an Issuer or Subsidiary Guarantor that was Incurred in
         accordance with the terms of this Indenture,

                  (xiii) the accrual of interest, the accretion or amortization
         of original issue discount, the payment of interest on any Indebtedness
         in the form of additional Indebtedness with the same terms, provided,
         in each such case, that the amount thereof is included in Consolidated
         Fixed Charges of NATG as accrued,

                                      -15-

<PAGE>   20

                  (xiv) the Incurrence by a Receivables Entity of Indebtedness
         in a Qualified Receivables Transaction that is Non-Recourse Debt
         (except for Standard Securitization Undertakings),

                  (xv) customary earn-out obligations owing in connection with
         any Asset Acquisition,

                  (xvi) unsecured Indebtedness of Restricted Subsidiaries of
         NATG not organized under the laws of the United States or any state
         thereof and consisting of working capital lines of credit in an
         aggregate amount not to exceed the dollar equivalent of $5.0 million at
         any time outstanding,

                  (xvii) the Incurrence of Indebtedness arising from the
         endorsement of negotiable instruments in the ordinary course of
         business, and

                  (xviii) additional unsecured Indebtedness of NATG or its
         Restricted Subsidiaries (other than Contingent Obligations NATG or its
         Restricted Subsidiaries with respect to Junior Subordinated Notes) in
         an aggregate principal amount not to exceed $5.0 million at any one
         time outstanding.

         "Permitted Investments" means (i) Investments by NATG or any Restricted
Subsidiary of NATG (other than a Receivables Entity) in a Person if as a result
of such Investment such Person transfers or conveys all or substantially all of
its assets to NATG or any Restricted Subsidiary of NATG (other than a
Receivables Entity); provided, that such Person's primary business is a
Permitted Business, (ii) Investments by NATG or any Restricted Subsidiary of
NATG (other than a Receivables Entity) in NATG or any Restricted Subsidiary of
NATG (other than a Receivables Entity) or in any Person if, as a result of such
Investment, such Person shall become, whether by consolidation, merger or
otherwise, a Restricted Subsidiary of NATG; provided, that such Person's primary
business is a Permitted Business, (iii) Investments by NATG or its Restricted
Subsidiaries existing on the Issue Date (which shall exclude any Investment
described in clause (ix) below), (iv) Investments in cash and Cash Equivalents,
(v) loans and advances to employees and officers of Parent and its Restricted
Subsidiaries in the ordinary course of business for bona fide business purposes
not in excess of $1.0 million at any one time outstanding, (vi) Interest Rate
Agreements entered into in the ordinary course of NATG's or its Restricted
Subsidiaries' businesses and otherwise in compliance with this Indenture, (vii)
Investments in securities of trade creditors or customers received pursuant to
any plan of reorganization or similar arrangement upon the bankruptcy or
insolvency of such trade creditors or customers, (viii) Investments made by NATG
or its Subsidiaries as a result of consideration received in connection with an
Asset Sale made in compliance with Section 4.16, (ix) Investments in
women/minority owned business enterprises in an aggregate amount not to exceed
$5.0 million at any time, (x) deposits made in the ordinary course of business
consistent with past practices to secure the performance of leases, and (xi)
Investments by NATG or any Guarantor in a Receivables Subsidiary or any
Investment by a Receivables Subsidiary in any other Person, in each case in
connection with a Qualified Receivables Transaction; provided, that any such
Investment in a Receivables Entity is in the form

                                      -16-

<PAGE>   21

of a Purchase Money Note or an equity interest, (xii) Indebtedness permitted to
be incurred under Section 4.4, and (xiii) additional Investments not to exceed
$5.0 million at any time.

         "Permitted Liens" means

                  (i) Liens for taxes or claims either (a) not delinquent or (b)
         contested in good faith by appropriate proceedings and as to which
         Parent or a Subsidiary shall have set aside on its books such reserves
         as may be required by GAAP,

                  (ii) statutory Liens of landlords and Liens of carriers,
         warehousemen, mechanics and materialmen and other Liens imposed by law
         incurred in the ordinary course of business for sums not yet delinquent
         or being contested in good faith by appropriate proceedings; provided,
         that (x) any proceedings commenced for the enforcement of such Liens
         shall have been stayed or suspended within 30 days of the commencement
         thereof and (y) a reserve or other appropriate provision, if any, as
         shall be required by GAAP shall have been made therefor,

                  (iii) Liens incurred or deposits made in the ordinary course
         of business in connection with workers' compensation, unemployment
         insurance and other types of social security, or to secure the
         performance of tenders, statutory obligations, surety and appeal bonds,
         bids, leases, government contracts, trade contracts, performance and
         return-of-money bonds and other similar obligations (exclusive of
         obligations for the payment of borrowed money),

                  (iv) any attachment or judgment Lien not constituting an Event
         of Default under Section 6.1(e),

                  (v) Permitted Real Property Encumbrances, easements,
         rights-of-way, restrictions, minor defects, encroachments or
         irregularities in title and other similar charges or encumbrances not
         interfering in any material respect with the ordinary conduct of the
         business of Parent or any of its Restricted Subsidiaries,

                  (vi) any interest or title of a lessor under any Capitalized
         Lease Obligation or mortgage permitted to be Incurred under clause (xi)
         of the definition of Permitted Indebtedness; provided, that such Liens
         do not extend to any property or assets which is not leased property
         subject to such Capitalized Lease Obligation or mortgage or other
         property subject to a permitted Lien held by the Lien holder of such
         Capitalized Lease Obligation,

                  (vii) Liens to finance property or assets (including the cost
         of construction) of any Restricted Subsidiary of NATG acquired in the
         ordinary course of business; provided, that (A) the related Purchase
         Money Obligations shall be permitted to be Incurred under Section 4.4
         and shall not exceed the cost of such property or assets (including the
         cost of construction) and shall not be secured by any property or
         assets of NATG or any Restricted Subsidiary other than the property and
         assets so acquired and (B) the Lien securing such Indebtedness shall be
         created within 90 days of such acquisition or construction,

                                      -17-

<PAGE>   22

                  (viii) Liens encumbering deposits made to secure obligations
         arising from statutory, regulatory, contractual, or warranty
         requirements of NATG or any of its Restricted Subsidiaries, including
         rights of offset and set-off,

                  (ix) Liens arising out of consignment or similar arrangements
         for the sale of goods in the ordinary course of business,

                  (x) leases or subleases granted to others that do not
         materially interfere with the ordinary course of business of Parent and
         its Restricted Subsidiaries,

                  (xi) Liens arising from filing Uniform Commercial Code
         financing statements regarding leases,

                  (xii) Liens in favor of TCI or any of its Affiliates securing
         advances made to NATG or any of its Restricted Subsidiaries pursuant to
         turnkey agreements entered into in the ordinary course of business with
         TCI or any of its Affiliates; provided, that such Liens shall only
         attach to property (including proceeds thereof) which is purchased with
         the applicable advance and shall automatically terminate when the
         applicable advance has been fully paid,

                  (xiii) Liens attaching solely to cash earnest money deposits
         made by NATG or any of its Restricted Subsidiaries in connection with
         any letter of intent or purchase agreement entered into by it in
         connection with an Asset Acquisition,

                  (xiv) Liens deemed to exist in connection with repurchase
         agreements and other similar Permitted Investments,

                  (xv) customary rights of set off, revocation, refund or
         chargeback under deposit agreements or under the UCC of banks or other
         financial institutions where any Issuer maintains deposits in the
         ordinary course of business permitted by this Indenture,

                  (xvi) Liens on accounts receivable for which attempts at
         collection have been undertaken by a third party authorized by the
         Person owing such accounts receivable,

                  (xvii) Liens arising from the granting of a license by NATG or
         any Restricted Subsidiary of NATG to any Person in the ordinary course
         of business,

                  (xviii) Liens arising by operation of law on insurance
         policies and proceeds thereof to secure premiums thereunder,

                  (xix) Liens relating solely to assets to be sold in any Asset
         Sale permitted in this Indenture and arising pursuant to the sale
         agreements governing such Asset Sale,

                  (xx) Liens on property of a Person existing at the time such
         Person is acquired by, merged with or into, or consolidated with NATG
         or any Restricted Subsidiary of NATG; provided, that such Liens were in
         existence prior to the contemplation of such

                                      -18-

<PAGE>   23

acquisition, merger or consolidation and do not extend to any assets other than
those of the Person acquiring merged into or consolidated with NATG or the
Restricted Subsidiary,

                  (xxi)    Liens existing on the Issue Date,

                  (xxii) Liens on assets transferred to a Receivables Entity or
         on assets of a Receivables Entity, in either case incurred in
         connection with a Qualified Receivables Transaction, and

                  (xxiii) Liens incurred in the ordinary course of business of
         any Restricted Subsidiary of NATG with respect to obligations that do
         not exceed $3.0 million in the aggregate at any one time outstanding
         and that (a) are not incurred in connection with the borrowing of money
         or the obtaining of advances or credit (other than trade credit in the
         ordinary course of business) and (b) do not in the aggregate materially
         detract from the value of the property or materially impair the use
         thereof in the operation of business by such Restricted Subsidiary.

         "Permitted Real Property Encumbrances" means (i) those Liens,
encumbrances and other matters affecting title to any real property securing
Senior Debt to the extent found reasonably acceptable by the agent for such
Senior Debt, (ii) such easements, encroachments, covenants, rights of way, minor
defects, irregularities, encumbrances on title or similar restrictions on any
real property securing Senior Debt which do not, in the reasonable opinion of
the agents for such Senior Debt, materially impair such real property for the
purposes for which it is held by the owner or lessor thereof or the Lien thereon
created in favor of such Senior Debt, and (iii) municipal and zoning ordinances,
which are not violated in any material respect by the existing improvements and
the present use of any real property securing Senior Debt.

         "Permitted Refinancing Indebtedness" means any Refinancing by NATG or
any Restricted Subsidiary of NATG of Indebtedness incurred in accordance with
Section 4.4 (other than pursuant to clauses (ii), (iv), (v), (vi), (vii),
(viii), (ix), (x), (xi), (xii), (xiii), (xiv), (xv), (xvi), (xvii), or (xviii)
of the definition of Permitted Indebtedness), in each case that does not (A)
result in an increase in the aggregate principal amount of Indebtedness of such
Person as of the date of such proposed Refinancing, (plus the amount of any
premium required to be paid under the terms of the instrument governing such
Indebtedness and plus the amount of reasonable expenses Incurred by such Person
in connections with such Refinancing), or (B) create Indebtedness with: (1) a
Weighted Average Life to Maturity that is less than the Weighted Average Life to
Maturity of the Indebtedness being Refinanced or (2) a final maturity earlier
than the final maturity of the Indebtedness being Refinanced,

provided, that if (x) such Indebtedness being Refinanced ranked pari passu with
the Securities or the Guarantees, such Refinancing Indebtedness shall rank
either pari passu with or junior to the Securities or the Guarantees, as
applicable, and (y) such Indebtedness being Refinanced constituted Subordinated
Indebtedness, such Refinancing Indebtedness shall be subordinated to the
Securities and the Guarantees, as applicable, at least to the same extent and in
the same manner as the Indebtedness being Refinanced.

                                      -19-

<PAGE>   24

         "Person" means any individual, partnership, joint venture, firm,
corporation, limited liability company, association, trust or other enterprise
or any government or political subdivision or any agency, department or
instrumentality thereof.

         "Physical Securities" has the meaning provided in Section 2.1.

         "Principal" or "principal" of any Indebtedness (including the
Securities) means the principal amount of such Indebtedness plus the premium, if
any, on such Indebtedness; provided, that in the case of Indebtedness issued
with original issue discount, "Principal" or "principal" shall refer to the
accreted value of such Indebtedness.

         "Private Exchange Security" means the "Private Exchange Notes" as
defined in the Registration Rights Agreement and any similar Securities issued
in compliance with Section 2.2 in accordance with any other registration rights
agreement.

         "Private Placement Legend" means the legends initially set forth on the
Securities in the form set forth in Exhibit B.

         "Pro Forma Adjustments" means, with respect to a particular Asset
Acquisition, adjustments to eliminate the effect of any non-recurring expenses
or income from such Asset Acquisition with respect to NATG and its Restricted
Subsidiaries or any acquired Person or assets on Consolidated EBITDA, determined
in good faith by the chief financial officer of Parent and approved by the Board
of Directors of Parent, as set forth in an Officers' Certificate delivered to
the Trustee setting forth in reasonable detail the basis for such adjustments.

         "Purchase Money Note" means a promissory note of a Receivables Entity
evidencing a line of credit, which may be irrevocable, from NATG or any of its
Restricted Subsidiaries to a Receivables Entity in connection with a Qualified
Receivables Transaction which note shall be repaid from cash available to the
Receivables Entity, other than amounts required to be established as reserves
pursuant to agreements, amounts paid to investors in respect of interest,
principal and other amounts owing to such investors and amounts paid in
connection with the purchase of newly generated receivables.

         "Purchase Money Obligations" of any Person shall mean any obligations
of such Person or any of its Restricted Subsidiaries to any seller or any other
Person incurred or assumed in connection with the purchase of real or personal
property to be used in the business of such Person or any of its Restricted
Subsidiaries within 180 days of such purchase.

         "Put/Call Agreement" means the Orius Call Agreements, Orius Put
Agreements, HIG Call Agreements and HIG Put Agreements, as each such term is
defined in the Reorganization Agreement and as each may be amended, restated,
supplemented or otherwise modified from time to time.

         "Qualified Capital Stock" means any Capital Stock that is not
Disqualified Capital Stock or that is not Indebtedness that is convertible or
exchangeable into Capital Stock.

                                      -20-

<PAGE>   25

         "Qualified Institutional Buyer" or "QIB" shall have the meaning
specified in Rule 144A under the Securities Act.

         "Qualified IPO" means a bona fide underwritten sale to the public of
Parent Common Stock pursuant to a registration statement (other than on Form S-8
or any other form relating to securities issuable under any benefit plan of
Parent or any of its Restricted Subsidiaries, as the case may be) that is
declared effective by the SEC and such offering results in gross cash proceeds
(exclusive of underwriter's discounts and commissions and other expenses) of at
least $50.0 million.

         "Qualified Receivables Transaction" means any transaction or series of
transactions pursuant to which NATG or any of its Restricted Subsidiaries may
sell, convey or otherwise transfer to (a) a Receivables Entity (in the case of a
transfer by NATG or any of its Restricted Subsidiaries) and (b) any other Person
(in case of a transfer by a Receivables Entity), or may grant a security
interest in, any accounts receivable (whether now existing or arising or
acquired in the future) of NATG or any of its Restricted Subsidiaries, and any
assets related thereto including, without limitation, all collateral securing
such accounts receivable, all contracts and contract rights and all guarantees
or other obligations in respect to such accounts receivable and equipment,
proceeds of such accounts receivable and other assets (including contract
rights) which are customarily transferred or in respect of which security
interests are customarily granted in connection with asset securitization
transactions involving accounts receivable, all of the foregoing for the purpose
of providing working capital financing on terms that are more favorable to NATG
and its Restricted Subsidiary than would otherwise be available at that time.

         "Receivables Entity" means a Wholly Owned Subsidiary of NATG (or
another Person in which NATG or any Restricted Subsidiary of NATG makes an
Investment and to which NATG or any Restricted Subsidiary of NATG transfers
accounts receivable and related assets) that engages in no activities other than
in connection with the financing of accounts receivable and that is designated
by the Board of Directors of NATG (as provided below) as a Receivables Entity
(a) no portion of the Indebtedness or any other obligations (contingent or
otherwise) of which (i) is guaranteed by NATG or any of its Restricted
Subsidiaries (other than such Receivables Entity), excluding guarantees of
obligations (other than the principal of, and interest on, Indebtedness)
pursuant to Standard Securitization Undertakings, (ii) is recourse to or
obligates NATG or any of its Restricted Subsidiaries (other than such
Receivables Entity) in any way other than pursuant to Standard Securitization
Undertakings or (iii) subjects any property or asset of NATG or any of its
Restricted Subsidiaries (other than such Receivables Entity), directly or
indirectly, contingently or otherwise, to the satisfaction thereof, other than
pursuant to Standard Securitization Undertakings, (b) with which neither NATG
nor any of its Restricted Subsidiaries (other than such Receivables Entity) has
any material contract, agreement, arrangement or understanding other than on
terms no less favorable to NATG or such Restricted Subsidiary than those that
might be obtained at the time from Persons that are not Affiliates of Parent,
other than fees payable in the ordinary course of business in connection with
servicing receivables of such entity, and (c) to which neither NATG nor any
Restricted Subsidiary of NATG (other than such Receivables Entity) has any
obligation to maintain or preserve such entity's financial condition or cause
such entity to achieve certain levels of operating results. Any such designation
by the Board of Directors shall be evidenced to the

                                      -21-

<PAGE>   26

Trustee by filing with the Trustee a certified copy of the resolution of the
Board of Directors giving effect to such designation and an Officers'
Certificate certifying that such designation complied with the foregoing
conditions.

         "Record Date" means the applicable Record Date specified in the
Securities; provided, that if any such date is not a Business Day, the Record
Date shall be the first day immediately preceding such specified day that is a
Business Day.

         "Redemption Date," when used with respect to any Security to be
redeemed, means the date fixed for such redemption pursuant to this Indenture
and the Securities.

         "Redemption Price," when used with respect to any Security to be
redeemed, means the price fixed for such redemption, payable in immediately
available funds, pursuant to this Indenture and the Securities.

         "Reference Date" has the meaning set forth in Section 4.3.

         "Refinance" means, in respect of any security or Indebtedness, to
refinance, extend, renew, refund, repay, prepay, redeem, defease or retire, or
to issue a security or Indebtedness in exchange or replacement for, such
security or Indebtedness in whole or in part. "Refinanced" and "Refinancing"
shall have correlative meanings.

         "Registrar" has the meaning set forth in Section 2.3.

         "Registration Rights Agreement" means means the Registration Rights
Agreement dated as of the Issue Date among the Issuers, the Guarantors and the
Initial Purchasers.

         "Regulation S" means Regulation S under the Securities Act.

         "Regulation S Global Security" means a permanent global security in
registered form representing the aggregate principal amount of Securities from
time to time sold in reliance on Regulation S under the Securities Act.

         "Reorganization Agreement" means the Agreement and Plan of
Reorganization, dated November 8, 1999, by and among LISN Holdings, Parent and
Orius Merger Sub, Inc.

         "Replacement Assets" has the meaning set forth in Section 4.16.

         "Representative" means the indenture trustee or other trustee, agent or
representative in respect of any Designated Senior Debt; provided, that if, and
for so long as, any Designated Senior Debt lacks such a representative, then the
Representative for such Designated Senior Debt shall at all times be the holders
of a majority in outstanding principal amount of such Designated Senior Debt in
respect of any Designated Senior Debt.

         "Responsible Officer" means, when used with respect to the Trustee, any
officer in the corporate trust office of the Trustee including any vice
president, assistant vice president, assistant secretary, treasurer, assistant
treasurer, or any other officer of the Trustee who

                                      -22-

<PAGE>   27

customarily performs functions similar to those performed by the Persons who at
the time shall be such officers, respectively, or to whom any corporate trust
matter is referred because of such officer's knowledge of and familiarity with
the particular subject.

         "Restricted Investment" means any investment other than a Permitted
Investment.

         "Restricted Payment" has the meaning set forth in Section 4.3.

         "Restricted Security" means a Security that constitutes a "Restricted
Security" within the meaning of Rule 144(a)(3) under the Securities Act;
provided, that the Trustee shall be entitled to request and conclusively rely on
an Opinion of Counsel with respect to whether any Security constitutes a
Restricted Security.

         "Restricted Subsidiary" of any Person means any Subsidiary of such
Person which at the time of determination is not an Unrestricted Subsidiary. For
the avoidance of doubt, the Issuers shall be deemed to be Restricted
Subsidiaries of Parent, and the Corporate Issuer shall be deemed to be a
Restricted Subsidiary of NATG.

         "Revolving Loans" means all Revolving Loans under and as defined in the
Senior Secured Credit Agreement as in effect on the Issue Date.

         "Rollover Letters of Credit" means all Rollover Letters of Credit under
and as defined in the Senior Secured Credit Agreement as in effect on the Issue
Date.

         "Rule 144A" means Rule 144A under the Securities Act.

         "S&P" means Standard & Poor's Ratings Services.

         "Securities" means, collectively, the Issuers' 12 3/4% Senior
Subordinated Notes due 2010 issued under this Indenture (whether on the Issue
Date or thereafter) and any Exchange Securities issued in exchange therefor,
treated as a single class of securities under this Indenture, as amended or
supplemented from time to time in accordance with the terms of this Indenture.

         "Securities Act" means the Securities Act of 1933, as amended, or any
successor statute or statutes thereto.

         "Securityholder" or "Holder" means the Person in whose name a Security
is registered on the Registrar's books.

         "Senior Debt" means the principal of, premium, if any, interest
(including any interest accruing subsequent to the filing of a petition of
bankruptcy at the rate provided for in the documentation with respect thereto,
whether or not such interest is an allowed claim under applicable law), fees and
expenses on any Indebtedness of an Issuer, whether outstanding on the Issue Date
or thereafter created, incurred, assumed or guaranteed, unless, in the case of
any particular Indebtedness, the instrument creating or evidencing the same or
pursuant to which the same is outstanding expressly provides that such
Indebtedness shall not be senior in right of payment to the Securities. Without
limiting the generality of the foregoing, "Senior Debt" shall also

                                      -23-

<PAGE>   28

include the principal of, premium, if any, interest (including any interest
accruing subsequent to the filing of a petition of bankruptcy at the rate
provided for in the documentation with respect thereto, whether or not such
interest is an allowed claim under applicable law) on, and all other amounts
owing in respect of, (x) all monetary obligations of every nature under the
Senior Secured Credit Agreement, including, without limitation, obligations to
pay principal and interest, reimbursement obligations under letters of credit,
fees, expenses and indemnities and (y) all IRA Obligations, in each case whether
outstanding on the Issue Date or thereafter incurred. Notwithstanding the
foregoing, "Senior Debt" shall not include (i) any Indebtedness of an Issuer to
a Subsidiary of Parent, (ii) any Indebtedness to, or guaranteed on behalf of,
any director, officer or employee of Parent or any of its Subsidiaries
(including, without limitation, amounts owed for compensation), (iii)
Indebtedness to trade creditors and other amounts incurred in connection with
obtaining goods, materials or services, (iv) Indebtedness represented by
Disqualified Capital Stock, (v) any liability for federal, state, local or other
taxes owed or owing by an Issuer, (vi) Indebtedness to the extent incurred in
violation of Section 4.4, (vii) Indebtedness which, when incurred and without
respect to any election under Section 1111(b) of Title 11, United States Code,
is without recourse to an Issuer and (viii) any Indebtedness which is, by its
express terms, subordinated in right of payment to any other Indebtedness of an
Issuer.

         "Senior Loans" means all Loans under and as defined in the Senior
Secured Credit Agreement.

         "Senior Secured Credit Agreement" means the Credit Agreement, dated as
of December 15, 1999, among NATG, LISN, LLC, the various lending institutions
party thereto, and Bankers Trust Company, as Agent, together with the documents
related thereto (including, without limitation, any guaranty agreements and
security documents), in each case as such agreements may be amended (including
any amendment and restatement thereof), supplemented, replaced, refinanced or
otherwise modified from time to time, including any agreement extending the
maturity of, refinancing, replacing or otherwise restructuring (including
increasing the amount of available borrowings thereunder, (provided, that such
increased amount is permitted by Section 4.4 or adding or deleting Subsidiaries
as additional borrowers or guarantors thereunder) all or any portion of the
Indebtedness under such agreement or any successor or replacement agreement and
whether by the same or any other agent, lender or group of lenders.

         "Senior Term Loan" means all Term Loans under and as defined in the
Senior Secured Credit Agreement as in effect on the Issue Date and shall include
any Acquisition Term Loans (as defined in the Senior Secured Credit Agreement as
in effect on the Issue Date) to the extent termed out and any subsequent term
loans under the Senior Secured Credit Agreement that refinance such Term Loans
or Acquisition Term Loans (or any subsequent term loans).

         "Significant Subsidiary," with respect to any Person, means any
Restricted Subsidiary of such Person that satisfies the criteria for a
"significant subsidiary" set forth in Rule 1.02(w) of Regulation S-X under the
Securities Act.

                                      -24-

<PAGE>   29

         "Standard Securitization Undertakings" means representations,
warranties, covenants and indemnities entered into by NATG or any Subsidiary of
NATG that are reasonably customary in Qualified Receivables Transactions
intended to create Non-Recourse Debt.

         "Subordinated Indebtedness" means Indebtedness of any Issuer or
Guarantor which is expressly subordinated in right of payment to the obligations
of such Issuer or Guarantor in respect of this Indenture, the Securities and the
Guarantees, as applicable.

         "Subsidiary" means, with respect to any Person, any corporation,
partnership, association, joint venture or other business entity of which more
than 50% of the total voting power of shares of stock or other ownership
interests entitled (without regard to the occurrence of any contingency) to vote
in the election of the Person or Persons (whether directors, managers, trustees
or other Persons performing similar functions) having the power to direct or
cause the direction of the management and policies thereof is at the time owned
or controlled, directly or indirectly, by that Person or one or more of the
other Subsidiaries of that Person or a combination thereof.

         "Subsidiary Guarantor" means any Guarantor that is also a Subsidiary of
NATG.

         "Surviving Entity" has the meaning set forth in Section 5.1.

         "Synthetic Arrangement" means any derivative product that provides for
the synthetic purchase or repurchase of any Indebtedness or securities
(including equity and debt securities).

         "TCI" shall mean TCI Atlantic, Inc., a Colorado corporation.

         "Temporary Reg. S Global Security" shall have the meaning provided in
Section 2.1.

         "TIA" means the Trust Indenture act of 1939 (15 U.S.C. ss.ss.
77aaa-77bbbb), as amended, as in effect on the Issue Date until such time as
this Indenture is qualified under the TIA, and thereafter as in effect on the
date on which this Indenture is qualified under the TIA, except as otherwise
provided in Section 9.4.

         "Trust Officer" means any officer or assistant officer of the Trustee
assigned by the Trustee to administer its corporate trust matters or, in the
case of a successor trustee, an officer assigned to the department, division or
group performing the corporate trust work of such successor.

         "Trustee" means the party named as such in this Indenture until a
successor replaces it in accordance with the provisions of this Indenture and
thereafter means such successor.

         "Unrestricted Securities" means one or more Securities that do not and
are not required to bear the Private Placement Legend in the form set forth in
Exhibit B, including, without limitation, the Exchange Securities.

         "Unrestricted Subsidiary" of any Person means (i) any Subsidiary of
such Person that at the time of determination shall be or continue to be
designated an Unrestricted Subsidiary by the Board of Directors of such Person
in the manner provided below and (ii) any Subsidiary of an Unrestricted

                                      -25-

<PAGE>   30

Subsidiary. The Board of Directors of a Person may designate any Subsidiary
(including any newly acquired or newly formed Subsidiary) of such Person to be
an Unrestricted Subsidiary unless such Subsidiary owns any Capital Stock of, or
owns or holds any Lien on any property of, Parent or any other Restricted
Subsidiary of Parent that is not a Subsidiary of the Subsidiary to be so
designated; provided, that (x) Parent delivers a copy of the relevant Board
Resolution to the Trustee together with an Officers' Certificate from Parent
certifying that such designation complies with the terms of this Indenture,
including the requirements set forth in this definition and in Section 4.4 and
(y) each Subsidiary to be so designated and each of its Subsidiaries has not at
the time of designation, and does not thereafter, create, incur, issue, assume,
guarantee or otherwise become directly or indirectly liable with respect to any
Indebtedness pursuant to which the lender has recourse to any of the assets of
Parent or any of its Restricted Subsidiaries; and, provided, further, that under
no circumstances may an Issuer be designated as an Unrestricted Subsidiary. The
Board of Directors may designate any Unrestricted Subsidiary to be a Restricted
Subsidiary only if (x) immediately after giving effect to such designation,
Parent would be able to incur at least $1.00 of additional Indebtedness (other
than Permitted Indebtedness) in compliance with Section 4.4 and (y) immediately
before and immediately after giving effect to such designation, no Default or
Event of Default shall have occurred and be continuing. Any such designation
shall be evidenced to the Trustee by promptly filing with the Trustee a copy of
the Board Resolution giving effect to such designation and an Officers'
Certificate from Parent certifying that such designation complied with the
foregoing provisions.

         "U.S. Government Obligations" means direct obligations of, and
obligations guaranteed by, the United States of America for the payment of which
the full faith and credit of the United States of America is pledged and which
are not callable or redeemable at the issuer's option.

         "U.S. Legal Tender" means such coin or currency of the United States of
America as at the time of payment shall be legal tender for the payment of
public and private debts.

         "U.S. Person" has the meaning set forth in Regulation S.

         "Voting Securities" means any class of Capital Stock of a Person
pursuant to which the holders thereof have, at the time of determination, the
general voting power under ordinary circumstances to vote for the election of
directors, managers, trustees or general partners of such Person (irrespective
of whether or not at the time any other class or classes will have or might have
voting power by reason of the happening of any contingency).

         "Weighted Average Life to Maturity" means, when applied to any
Indebtedness at any date, the number of years obtained by dividing (a) the then
outstanding aggregate principal amount of such Indebtedness into (b) the sum of
the total of the products obtained by multiplying (i) the amount of each then
remaining installment, sinking fund, serial maturity, or other required payment
of principal, including payment at final maturity, in respect thereof, by (ii)
the number of years (calculated to the nearest one-twelfth) which will elapse
between such date and the making of such payment.

                                      -26-

<PAGE>   31

         "Wholly Owned Restricted Subsidiary" of any Person means any Wholly
Owned Subsidiary of such Person which at the time of determination is a
Restricted Subsidiary of such Person.

         "Wholly Owned Subsidiary" of any Person means any Subsidiary of such
Person of which all the outstanding Voting Securities (other than in the case of
a foreign Subsidiary, directors' qualifying shares or an immaterial amount of
shares required to be owned by other Persons pursuant to applicable law) are
owned by such Person or any Wholly Owned Subsidiary of such Person.

         "Written" or "in writing" shall mean any form of written communication
or a communication by means of facsimile transmission, telegraph or cable.

         "WSP" means Willis Stein & Partners II, L.P. and Willis Stein &
Partners Dutch, L.P.

         Section 1.2 Incorporation by Reference of TIA. Whenever this Indenture
refers to a provision of the TIA, such provision is incorporated by reference
in, and made a part of, this Indenture. The following TIA terms used in this
Indenture have the following meanings:

         "indenture securities" means the Securities.

         "indenture security holder" means a Holder or a Securityholder.

         "indenture to be qualified" means this Indenture.

         "indenture trustee" or "institutional trustee" means the Trustee.

         "obligor" on the indenture securities means the Issuers, any Guarantor
or any other obligor on the Securities.

         All other TIA terms used in this Indenture that are defined by the TIA,
defined by TIA reference to another statute or defined by Commission rule and
not otherwise defined herein have the meanings assigned to them therein.

         Section 1.3 Rules of Construction. Unless the context otherwise
requires:

         (1) a term has the meaning assigned to it;

         (2) an accounting term not otherwise defined has the meaning assigned
to it in accordance with GAAP;

         (3) "or" is not exclusive;

         (4) words in the singular include the plural, and words in the plural
include the singular;

         (5) provisions apply to successive events and transactions; and

                                      -27-

<PAGE>   32

         (6) "herein," "hereof" and other words of similar import refer to this
Indenture as a whole and not to any particular Article, Section or other
subdivision.

         Section 1.4 Ancillary Agreements. The Trustee is hereby authorized and
directed to execute and deliver such agreements, notices, certificates and
assignments as are necessary to implement the terms of this Indenture, including
but not limited to the letter of representations with the Depository.

                                   ARTICLE TWO

                                 THE SECURITIES

         Section 2.1 Form and Dating. The Securities and the Trustee's
certificate of authentication shall be substantially in the form of Exhibit A.
The Securities may have notations, legends or endorsements required by law,
stock exchange rule or usage. The Issuers shall approve the form of the
Securities and any notation, legend or endorsement on them. Each Security shall
be dated the date of its issuance and show the date of its authentication. Each
Security shall have an executed Guarantee from each of the Guarantors endorsed
thereon substantially in the form of Exhibit E.

         The terms and provisions contained in the Securities and the Guarantees
shall constitute, and are hereby expressly made, a part of this Indenture and,
to the extent applicable, the Issuers, the Guarantors and the Trustee, by their
execution and delivery of this Indenture, expressly agree to such terms and
provisions and to be bound thereby. Securities offered and sold to QIBs in
reliance on Rule 144A, Securities offered and sold in reliance on Regulation S
and Securities offered and sold to Institutional Accredited Investors in
reliance on Regulation D of the Securities Act shall be issued initially in the
form of one or more Global Securities, substantially in the form set forth in
Exhibit A, deposited with the Trustee, as custodian for the Depository, duly
executed by the Issuers (and having an executed Guarantee from each of the
Guarantors endorsed thereon) and authenticated by the Trustee as hereinafter
provided and shall bear the legends set forth in Exhibit B. Securities initially
offered and sold in offshore transactions pursuant to Regulation S under the
Securities Act shall initially be issued in the form of a temporary Global
Security in registered form, deposited with the Trustee as custodian for the
Depositary (the "Temporary Reg. S Global Security"). Upon the expiration of the
Distribution Compliance Period, and upon receipt by the Trustee of the
certification required by Regulation S under the Securities Act, the Temporary
Reg. S Global Security shall be exchanged for the Regulation S Global Security
in equal principal amount. The aggregate principal amount of the Global
Securities may from time to time be increased or decreased by adjustments made
on the records of the Trustee, as custodian for the Depository, as hereinafter
provided.

         Securities issued in exchange for interests in a Global Security
pursuant to Section 2.16 may be issued in the form of permanent certificated
Securities in registered form in substantially the form set forth in Exhibit A
(the "Physical Securities").

         Section 2.2 Execution and Authentication. Two Officers, or an Officer
and an Assistant

                                      -28-

<PAGE>   33

Secretary, shall sign, or one Officer shall sign and one Officer or an Assistant
Secretary (each of whom shall, in each case, have been duty authorized by all
requisite limited liability company or corporate actions, as the case may be)
shall attest to, the Securities for each of the Issuers by manual or facsimile
signature.

         If an Officer whose signature is on a Security or Guarantee, as the
case may be, was an Officer at the time of such execution but no longer holds
that office at the time the Trustee authenticates the Security, the Security or
such Guarantee shall nevertheless be valid.

         A Security shall not be valid until an authorized signatory of the
Trustee manually signs the certificate of authentication on the Security. The
signature shall be conclusive evidence that the Security has been authenticated
under this Indenture.

         The Trustee shall authenticate (i) Initial Securities for original
issue in an aggregate principal amount not to exceed $300.0 million upon a
written order of the Issuers, provided that the aggregate principal amount of
Initial Securities issued on the Issue Date shall not exceed $150.0 million,
provided, further, that in connection with any Initial Securities originally
issued after the Issue Date, NATG complies with Section 4.4, (ii) Private
Exchange Securities from time to time only in exchange for a like principal
amount of the same type of Initial Securities in accordance with the terms of a
Registration Rights Agreement and (iii) Unrestricted Securities from time to
time (A) in exchange for a like principal amount of Initial Securities or a like
principal amount of Private Exchange Securities or (B) as the Issuers may
determine in accordance with this Indenture, in each case upon a written order
of each Issuer. Each such order shall specify the amount of Securities to be
authenticated and the date on which the Securities are to be authenticated. The
aggregate principal amount of Securities outstanding at any time may not exceed
$300.0 million, except as provided in Section 2.7.

         In the event that the Company shall issue and the Trustee shall
authenticate any Securities issued under this Indenture subsequent to the Issue
Date pursuant to clauses (i) and (iii) of the first sentence of the immediately
preceding paragraph, the Company shall use its reasonable efforts to obtain the
same "CUSIP" number for such Securities as is printed on the Securities
outstanding at such time.

         Notwithstanding the foregoing, all Securities issued under this
Indenture shall vote and consent together on all matters (as to which any of
such Securities may vote or consent) as one class and no series of Securities
will have the right to vote or consent as a separate class on any matter.

         The Trustee may appoint an authenticating agent reasonably acceptable
to the Issuers to authenticate Securities. Unless otherwise provided in the
appointment, an authenticating agent may authenticate Securities whenever the
Trustee may do so. Each reference in this Indenture to authentication by the
Trustee includes authentication by such agent. An authenticating agent has the
same rights as an Agent to deal with the Issuers and Affiliates of the Issuers.

         The Securities shall be issuable only in fully registered form without
coupons in denominations of $1,000 and integral multiples thereof.

                                      -29-

<PAGE>   34

         Section 2.3 Registrar and Paying Agent. The Issuers shall maintain an
office or agency in the Borough of Manhattan, The City of New York, where (a)
Securities may be presented or surrendered for registration of transfer or for
exchange ("Registrar"), (b) Securities may be presented or surrendered for
payment ("Paying Agent") and (c) notices and demands to or upon the Issuers in
respect of the Securities and this Indenture may be served. The Issuers may also
from time to time designate one or more other offices or agencies where the
Securities may be presented or surrendered for any or all such purposes and may
from time to time rescind such designations; provided, that no such designation
or rescission shall in any manner relieve the Issuers of their obligation to
maintain an office or agency in the Borough of Manhattan, The City of New York,
for such purposes. The Issuers may act as Registrar or Paying Agent except that
for the purposes of Articles Three and Eight and Sections 4.15 and 4.16, neither
the Issuers nor any Affiliate of the Issuers shall act as Paying Agent. The
Registrar shall keep a register of the Securities and of their transfer and
exchange. The Issuers, upon notice to the Trustee, may have one or more
co-Registrars and one or more additional paying agents reasonably acceptable to
the Trustee. The term "Paying Agent" includes any additional paying agent. The
Issuers initially appoint the Trustee as Registrar and Paying Agent until such
time as the Trustee has resigned or a successor has been appointed.

         The Issuers shall enter into an appropriate agency agreement with any
Agent not a party to this Indenture, which agreement shall implement the
provisions of this Indenture that relate to such Agent. The Issuers shall notify
the Trustee, in advance, of the name and address of any such Agent. If the
Issuers fail to maintain a Registrar or Paying Agent, the Trustee shall act as
such.

         Section 2.4 Paying Agent To Hold Assets in Trust. The Issuers shall
require each Paying Agent other than the Trustee to agree in writing that,
subject to Article Ten and Article Twelve, each Paying Agent shall hold in trust
for the benefit of Holders or the Trustee all assets held by the Paying Agent
for the payment of principal of, or interest on, the Securities (whether such
assets have been distributed to it by the Issuers or any other obligor on the
Securities), and shall notify the Trustee of any Default by the Issuers (or any
other obligor on the Securities) in making any such payment. If an Issuer or an
Affiliate of an Issuer acts as Paying Agent, it shall segregate such assets and
hold them as a separate trust fund. The Issuers at any time may require a Paying
Agent to distribute all assets held by it to the Trustee and account for any
assets disbursed and the Trustee may at any time during the continuance of any
payment default, upon written request to a Paying Agent, require such Paying
Agent to distribute all assets held by it to the Trustee and to account for any
assets distributed. Upon distribution to the Trustee of all assets that shall
have been delivered by the Issuers to the Paying Agent, the Paying Agent shall
have no further liability for such assets.

         Section 2.5 Holder Lists. The Trustee shall preserve in as current a
form as is reasonably practicable the most recent list available to it of the
names and addresses of Holders. If the Trustee is not the Registrar, the Issuers
shall furnish to the Trustee on or before each Interest Payment Date and at such
other times as the Trustee may request in writing a list in such form and as of
such date as the Trustee may reasonably require of the names and addresses of
Holders, which list may be conclusively relied upon by the Trustee.

                                      -30-

<PAGE>   35

         Section 2.6 Transfer and Exchange. Subject to Sections 2.15 and 2.16,
when Securities are presented to the Registrar or a co-Registrar with a request
to register the transfer of such Securities or to exchange such Securities for
an equal principal amount of Securities of other authorized denominations, the
Registrar or co-Registrar shall register the transfer or make the exchange as
requested if its requirements for such transaction are met; provided, that the
Securities surrendered for transfer or exchange shall be duly endorsed or
accompanied by a written instrument of transfer in form reasonably satisfactory
to the Issuers and the Registrar or co-Registrar, duly executed by the Holder
thereof or his attorney duly authorized in writing. To permit registrations of
transfers and exchanges, the Issuers shall execute and the Trustee shall
authenticate Securities at the Registrar's or co-Registrar's request. No service
charge shall be made for any registration of transfer or exchange, but the
Issuers may require payment of a sum sufficient to cover any transfer tax or
similar governmental charge payable in connection therewith (other than any such
tax or charge payable upon exchanges or transfers pursuant to Sections 2.10,
3.6, 4.15, 4.16 or 9.6). The Registrar or co-Registrar shall not be required to
register the transfer of or exchange of any Security (i) during a period
beginning at the opening of business 15 days before the mailing of a notice of
redemption of Securities and ending at the close of business on the day of such
mailing, (ii) selected for redemption in whole or in part pursuant to Article
Three, except the unredeemed portion of any Security being redeemed in part, and
(iii) during a Change of Control Offer or an Net Proceeds Offer if such Security
is tendered pursuant to such Change of Control Offer or Net Proceeds Offer and
not withdrawn.

         Any Holder of a beneficial interest in a Global Security shall, by
acceptance of such beneficial interest, agree that transfers of beneficial
interests in such Global Securities may be effected only through a book-entry
system maintained by the Holder of such Global Security (or its agent), and that
ownership of a beneficial interest in the Security shall be required to be
reflected in a book-entry system.

         Section 2.7 Replacement Securities. If a mutilated Security is
surrendered to the Trustee or if the Holder of a Security claims that the
Security has been lost, destroyed or wrongfully taken, the Issuers shall issue
and the Trustee shall authenticate a replacement Security if the Trustee's
requirements for replacement of Securities are met. If required by the Trustee
or the Issuers, such Holder must provide an indemnity bond or other indemnity,
sufficient in the reasonable judgment of both the Issuers and the Trustee, to
protect the Issuers, the Trustee or any Agent from any loss which any of them
may suffer if a Security is replaced. The Issuers may charge such Holder for
their reasonable out-of-pocket expenses in replacing a Security pursuant to this
Section 2.7, including reasonable fees and expenses of counsel.

         Every replacement Security is an additional obligation of the Issuers
and every replacement Guarantee shall constitute an additional obligation of the
Guarantors.

         Section 2.8 Outstanding Securities. Securities outstanding at any time
are all the Securities that have been authenticated by the Trustee except those
cancelled by it, those delivered to it for cancellation and those described in
this Section 2.8 as not outstanding. A Security does not cease to be outstanding
because the Issuers, the Guarantors or any of their respective Affiliates holds
such Security (subject to the provisions of Section 2.9).

                                      -31-

<PAGE>   36

         If a Security is replaced pursuant to Section 2.7 (other than a
mutilated Security surrendered for replacement), it ceases to be outstanding
unless the Trustee receives proof satisfactory to it that the replaced Security
is held by a bona fide protected purchaser. A mutilated Security ceases to be
outstanding upon surrender of such Security and replacement thereof pursuant to
Section 2.7. If the principal amount of any Security is considered paid under
Section 4.1, it ceases to be outstanding and interest ceases to accrue.

         If on a Redemption Date or the Maturity Date the Paying Agent (other
than Parent, an Issuer or any of their respective Affiliates) holds U.S. Legal
Tender or U.S. Government Obligations sufficient to pay all of the principal and
interest due on the Securities payable on that date, then on and after that date
such Securities shall cease to be outstanding and interest on them shall cease
to accrue.

         Section 2.9 Treasury Securities. In determining whether the Holders of
the required principal amount of Securities have concurred in any direction,
waiver or consent, Securities owned by Parent, any of its Subsidiaries or any of
their respective Affiliates shall be disregarded, except that, for the purposes
of determining whether the Trustee shall be protected in relying on any such
direction, waiver or consent, only Securities that the Trustee knows or has
reason to know are so owned shall be disregarded.

         Section 2.10 Temporary Securities. Until definitive Securities are
ready for delivery, the Issuers may prepare and the Trustee shall authenticate
temporary Securities. Temporary Securities shall be substantially in the form of
definitive Securities but may have variations that the Issuers reasonably
consider appropriate for temporary Securities. Without unreasonable delay, the
Issuers shall prepare and the Trustee shall authenticate definitive Securities
in exchange for temporary Securities. Until such exchange, temporary Securities
shall be entitled to the same rights, benefits and privileges as definitive
Securities. Notwithstanding the foregoing, so long as the Securities are
represented by a Global Security, such Global Security may be in typewritten
form. Notwithstanding the foregoing, this Section 2.10 shall not affect the
Issuers' obligations with respect to the Temporary Reg. S Global Security set
forth in Section 2.1.

         Section 2.11 Cancellation. An Issuer at any time may deliver Securities
to the Trustee for cancellation. The Registrar and the Paying Agent shall
forward to the Trustee any Securities surrendered to them for transfer, exchange
or payment. The Trustee, or at the direction of the Trustee, the Registrar or
the Paying Agent (other than Parent, an Issuer or any of their respective
Affiliates), and no one else, shall cancel and, at the written direction of the
Issuers, shall dispose of all Securities surrendered for transfer, exchange,
payment or cancellation. Subject to Section 2.7, the Issuers may not issue new
Securities to replace Securities that they have paid or delivered to the Trustee
for cancellation. If any Issuer or any Guarantor shall acquire any of the
Securities, such acquisition shall not operate as a redemption or satisfaction
of the Indebtedness represented by such Securities unless and until the same are
surrendered to the Trustee for cancellation pursuant to this Section 2.11.

                                      -32-

<PAGE>   37

         Section 2.12 Defaulted Interest. If the Issuers default in a payment of
interest on the Securities, they shall, unless the Trustee fixes another record
date pursuant to Section 6.10, pay the defaulted interest, plus (to the extent
lawful) any interest payable on the defaulted interest, in any lawful manner.
The Issuers may pay the defaulted interest to the persons who are Holders on a
subsequent special record date, which date shall be the fifteenth day next
preceding the date fixed by the Issuers for the payment of defaulted interest or
the next succeeding Business Day if such date is not a Business Day. At least 15
days before any such subsequent special record date, the Issuers shall mail to
each Holder, with a copy to the Trustee, a notice that states the subsequent
special record date, the payment date and the amount of defaulted interest, and
interest payable on such defaulted interest, if any, to be paid.

         Section 2.13 CUSIP Number. The Issuers in issuing the Securities shall
use "CUSIP" numbers, and if so, the Trustee shall use such CUSIP numbers in
notices of redemption or exchange as a convenience to Holders; provided, that
any such notice may state that no representation is made as to the correctness
or accuracy of the CUSIP numbers printed in the notice or on the Securities, and
that reliance may be placed only on the other identification numbers printed on
the Securities.

         Section 2.14 Deposit of Moneys. Prior to 11:00 a.m. New York City time
on each Interest Payment Date, Maturity Date, Redemption Date, Change of Control
Payment Date and Net Proceeds Offer Payment Date, the Issuers shall have
deposited with the Paying Agent in immediately available funds money sufficient
to make cash payments, if any, due on such Interest Payment Date, Maturity Date,
Redemption Date, Change of Control Payment Date and Net Proceeds Offer Payment
Date, as the case may be, in a timely manner which permits the Paying Agent to
remit payment to the Holders on such Interest Payment Date, Maturity Date,
Redemption Date, Change of Control Payment Date and Net Proceeds Offer Payment
Date, as the case may be.

         Section 2.15 Book-Entry Provisions for Global Securities. (a) The
Global Securities initially shall (i) be registered in the name of the
Depository or the nominee of such Depository, (ii) be delivered to the Trustee
as custodian for such Depository and (iii) bear legends as set forth in Exhibit
B.

         Members of, or participants in, the Depository ("Participants") shall
have no rights under this Indenture with respect to any Global Security held on
their behalf by the Depository, or the Trustee as its custodian, or under such
Global Security, and the Depository may be treated by the Issuers, the Trustee
and any agent of the Issuers or the Trustee as the absolute owner of such Global
Security for all purposes whatsoever. Notwithstanding the foregoing, nothing
herein shall prevent the Issuers, the Trustee or any agent of the Issuers or the
Trustee from giving effect to any written certification, proxy or other
authorization furnished by the Depository or impair, as between the Depository
and Participants, the operation of customary practices governing the exercise of
the rights of a Holder of any Security.

         (b) Transfers of Global Securities shall be limited to transfers in
whole, but not in part, to the Depository, its successors or their respective
nominees. Interests of beneficial owners in the

                                      -33-

<PAGE>   38

Global Securities may be transferred or exchanged for Physical Securities in
accordance with the rules and procedures of the Depository and the provisions of
Section 2.16. In addition, Physical Securities shall be transferred to all
beneficial owners in exchange for their beneficial interests in Global
Securities if (i) the Depository notifies the Issuers that it is unwilling or
unable to continue as Depository for any Global Security and a successor
Depository is not appointed by the Issuers within 90 days of such notice, (ii)
the Issuers notify the Trustee in writing that they elect to cause the issuance
of Securities in definitive form or (iii) an Event of Default has occurred and
is continuing and the Registrar has received a written request from the
Depository to issue Physical Securities.

         (c) In connection with any transfer or exchange of a portion of the
beneficial interest in a Global Security to beneficial owners pursuant to
paragraph (b), the Registrar shall (if one or more Physical Securities are to be
issued) reflect on its books and records the date and a decrease in the
principal amount of such Global Security in an amount equal to the principal
amount of the beneficial interest in the Global Security to be transferred, and
the Issuers shall execute, the Guarantors shall execute Guarantees, and the
Trustee shall authenticate and deliver, one or more Physical Securities of
authorized denominations in an aggregate principal amount equal to the principal
amount of the beneficial interest in the Global Security so transferred.

         (d) In connection with the transfer of a Global Security as an entirety
to beneficial owners pursuant to paragraph (b) of this Section 2.15, such Global
Security shall be deemed to be surrendered to the Trustee for cancellation, and
the Issuers shall execute, the Guarantors shall execute Guarantees on and the
Trustee shall upon written instructions from the Issuers authenticate and
deliver, to each beneficial owner identified by the Depository in exchange for
its beneficial interest in such Global Security, an equal aggregate principal
amount of Physical Securities of authorized denominations.

         (e) Any Physical Security constituting a Restricted Security delivered
in exchange for an interest in a Global Security pursuant to paragraph (b) or
(c) of this Section 2.15 shall, except as otherwise provided by Section 2.16,
bear the Private Placement Legend.

         (f) The Holder of any Global Security may grant proxies and otherwise
authorize any Person, including Participants and Persons that may hold interests
through Participants, to take any action which a Holder is entitled to take
under this Indenture or the Securities.

         Section 2.16 Special Transfer Provisions. (a) Transfers to Non-QIB
Institutional Accredited Investors and Non-U.S. Persons. The following
additional provisions shall apply with respect to the registration of any
proposed transfer of a Restricted Security to any Institutional Accredited
Investor which is not a QIB or to any Non-U.S. Person:

                  (i) the Registrar shall register the transfer of any
         Restricted Security, whether or not such Security bears the Private
         Placement Legend, if (x) the requested transfer is after the second
         anniversary of the initial date of issuance of such Security; provided,
         that neither the Issuers nor any Affiliate of the Issuers has held any
         beneficial interest in such Security, or portion thereof, at any time
         on or prior to such second anniversary or (y) (1) in the case of a
         transfer to an Institutional Accredited Investor which is not a QIB

                                      -34-

<PAGE>   39

         (excluding Non-U.S. Persons), the proposed transferee has delivered to
         the Registrar a certificate substantially in the form of Exhibit C and
         any legal opinions and certifications required thereby and (2) in the
         case of a transfer to a Non-U.S. Person, the transferor has delivered
         to the Registrar a certificate substantially in the form of Exhibit D;

                  (ii)  if the proposed transferee is a Participant and the
         Securities to be transferred consist of Physical Securities which after
         transfer are to be evidenced by an interest in the IAI Global Security,
         Temporary Reg. S Global Security or Regulation S Global Security, as
         the case may be, upon receipt by the Registrar of (x) written
         instructions given in accordance with the Depository's and the
         Registrar's procedures and (y) the appropriate certificate, if any,
         required by clause (y) of paragraph (i) above, the Registrar shall
         register the transfer and reflect on its books and records the date and
         an increase in the principal amount of the IAI Global Security,
         Temporary Reg. S Global Security or Regulation S Global Security, as
         the case may be, in an amount equal to the principal amount of Physical
         Securities to be transferred, and the Registrar shall cancel the
         Physical Securities so transferred; and

                  (iii) if the proposed transferor is a Participant seeking to
         transfer an interest in a Global Security, upon receipt by the
         Registrar of (x) written instructions given in accordance with the
         Depository's and the Registrar's procedures and (y) the appropriate
         certificate, if any, required by clause (y) of paragraph (i) above, the
         Registrar shall register the transfer and reflect on its books and
         records the date and (A) a decrease in the principal amount of the
         Global Security from which such interests are to be transferred in an
         amount equal to the principal amount of the Securities to be
         transferred and (B) an increase in the principal amount of the IAI
         Global Security or the Regulation S Global Security, as the case may
         be, in an amount equal to the principal amount of the Securities to be
         transferred.

         (b) Transfers to QIBs. The following provisions shall apply with
respect to the registration of any proposed transfer of a Restricted Security to
a QIB:

                  (i) the Registrar shall register the transfer of any
         Restricted Security, whether or not such Security bears the Private
         Placement Legend, if (x) the requested transfer is after the second
         anniversary of the initial date of issuance of such Security; provided,
         that neither the Issuers nor any Affiliate of the Issuers has held any
         beneficial interest in such Security, or portion thereof, at any time
         on or prior to the second anniversary of the initial date of issuance
         of such Security or (y) such transfer is being made by a proposed
         transferor who has checked the box provided for on the form of Security
         stating, or has otherwise advised the Issuers and the Registrar in
         writing, that the sale has been made in compliance with the provisions
         of Rule 144A to a transferee who has signed the certification provided
         for on the form of Security stating, or has otherwise advised the
         Issuers and the Registrar in writing, that it is purchasing the
         Security for its own account or an account with respect to which it
         exercises sole investment discretion and that it and any such account
         is a QIB within the meaning of Rule 144A, and is aware that the sale to
         it is being made in reliance on Rule 144A and acknowledges that it has
         received such

                                      -35-

<PAGE>   40

         information regarding the Issuers as it has requested pursuant to Rule
         144A or has determined not to request such information and that it is
         aware that the transferor is relying upon its foregoing representations
         in order to claim the exemption from registration provided by Rule
         144A;

                  (ii)  if the proposed transferee is a Participant and the
         Securities to be transferred consist of Physical Securities which after
         transfer are to be evidenced by an interest in the 144A Global
         Security, upon receipt by the Registrar of written instructions given
         in accordance with the Depository's and the Registrar's procedures, the
         Registrar shall, subject to clause (y) of paragraph (i) above, register
         the transfer and reflect on its book and records the date and an
         increase in the principal amount of the 144A Global Security in an
         amount equal to the principal amount of Physical Securities to be
         transferred, and the Registrar shall cancel the Physical Securities so
         transferred; and

                  (iii) if the proposed transferor is a Participant seeking to
         transfer an interest in the IAI Global Security or the Regulation S
         Global Security, upon receipt by the Registrar of written instructions
         given in accordance with the Depository's and the Registrar's
         procedures, the Registrar shall, subject to clause (y) of paragraph (i)
         above, register the transfer and reflect on its books and records the
         date and (A) a decrease in the principal amount of the IAI Global
         Security or the Regulation S Global Security, as the case may be, in an
         amount equal to the principal amount of the Securities to be
         transferred and (B) an increase in the principal amount of the 144A
         Global Security in an amount equal to the principal amount of the
         Securities to be transferred.

         (c) Restrictions on Transfer and Exchange of Global Securities.
Notwithstanding any other provisions of this Indenture, a Global Security may
not be transferred as a whole except by the Depository to a nominee of the
Depository or by a nominee of the Depository to the Depository or another
nominee of the Depository or by the Depository or any such nominee to a
successor Depository or a nominee of such successor Depository.

         (d) Private Placement Legend. Upon the transfer, exchange or
replacement of Securities not bearing the Private Placement Legend, the
Registrar or co-Registrar shall deliver Securities that do not bear the Private
Placement Legend. Upon the transfer, exchange or replacement of Securities
bearing the Private Placement Legend, the Registrar or co-Registrar shall
deliver only Securities that bear the Private Placement Legend unless (i) there
is delivered to the Trustee an Opinion of Counsel reasonably satisfactory to the
Issuers and the Trustee to the effect that neither such legend nor the related
restrictions on transfer are required in order to maintain compliance with the
provisions of the Securities Act or (ii) such Security has been sold pursuant to
an effective registration statement under the Securities Act.

         (e) Temporary Reg. S. Global Security. Notwithstanding anything to the
contrary in Section 2.15 or 2.16, interests in the Temporary Reg. S Global
Security may not be offered or sold to a U.S. Person (other than to a QIB that
takes delivery in the form of an interest in the Rule 144A Global Security or to
an Institutional Accredited Investor that takes delivery in the form of an
interest in the IAI Global Security, so long as the other requirements of this
Indenture

                                      -36-

<PAGE>   41

are met with respect to any such transfer) or for the account or benefit of a
U.S. Person prior to the expiration of the Distribution Compliance Period, and
no transfer or exchange of the Temporary Reg. S Global Security or interest in
the Temporary Reg. S Global Security may be made for a Physical Security or an
interest in a Physical Security until after the later of the date of expiration
of the Distribution Compliance Period and the date on which the certification
required by Regulation S relating to such transfer or exchange has been provided
to the effect that the beneficial owner or owners of such interest are not U.S.
Persons.

         (f) General. By its acceptance of any Security bearing the Private
Placement Legend, each Holder of such a Security acknowledges the restrictions
on transfer of such Security set forth in this Indenture and in the Private
Placement Legend and agrees that it will transfer such Security only as provided
in this Indenture.

         The Registrar shall retain copies of all letters, notices and other
written communications received pursuant to Section 2.15 or this Section 2.16.
The Issuers shall have the right to inspect and make copies of all such letters,
notices or other written communications at any reasonable time upon the giving
of reasonable written notice to the Registrar.

                                  ARTICLE THREE

                                   REDEMPTION

         Section 3.1 Notices to Trustee. If the Issuers elect to redeem
Securities pursuant to Section 3.7, they shall notify the Trustee in writing of
the Redemption Date, the Redemption Price and the principal amount of Securities
to be redeemed. The Issuers shall give notice of redemption to the Paying Agent
and Trustee at least 30 days but not more than 60 days before the Redemption
Date (unless a shorter notice shall be agreed to by the Trustee in writing),
together with an Officers' Certificate of each of them stating that such
redemption will comply with the conditions contained herein.

         Section 3.2 Selection of Securities To Be Redeemed. In the event that
less than all of the Securities are to be redeemed at any time, selection of
such Securities for redemption will be made by the Trustee in compliance with
the requirements of the principal national securities exchange, if any, on which
such Securities are listed or, if such Securities are not then listed on a
national securities exchange, on a pro rata basis, by lot or by such method as
the Trustee shall deem fair and appropriate; provided, that no Securities of a
principal amount of $1,000 or less shall be redeemed in part; and provided,
further, that if a partial redemption is made with the net cash proceeds of an
Equity Offering, selection of the Securities or portions thereof for redemption
shall be made by the Trustee only on a pro rata basis or on as nearly a pro rata
basis as is practicable (subject to the procedures of the Depository), unless
such method is otherwise prohibited.

         Section 3.3 Notice of Redemption. At least 30 days but not more than 60
days before a Redemption Date, the Issuers shall mail a notice of redemption by
first class mail, postage prepaid, to each Holder whose Securities are to be
redeemed at its registered address. At the

                                      -37-

<PAGE>   42

Issuers' request, the Trustee shall give the notice of redemption in the
Issuers' name and at the Issuers' expense. Each notice of redemption shall
identify the Securities to be redeemed and shall state:

                  (1)  the Redemption Date;

                  (2) the Redemption Price and the amount of accrued interest,
if any, to be paid;

                  (3)  the name and address of the Paying Agent;

                  (4) that Securities called for redemption must be surrendered
to the Paying Agent to collect the Redemption Price plus accrued interest, if
any;

                  (5) that, unless the Issuers defaults in making the redemption
payment, interest on Securities called for redemption ceases to accrue on and
after the Redemption Date, and the only remaining right of the Holders of such
Securities is to receive payment of the Redemption Price upon surrender to the
Paying Agent of the Securities redeemed;

                  (6) if any Security is being redeemed in part, the portion of
the principal amount of such Security to be redeemed and that, after the
Redemption Date, and upon surrender of such Security, a new Security or
Securities in aggregate principal amount equal to the unredeemed portion thereof
will be issued;

                  (7) if fewer than all the Securities are to be redeemed, the
identification of the particular Securities (or portion thereof) to be redeemed,
as well as the aggregate principal amount of Securities to be redeemed and the
aggregate principal amount of Securities to be outstanding after such partial
redemption; and

                  (8) the Section of this Indenture pursuant to which the
Securities are to be redeemed.

         The notice, if mailed in a manner herein provided, shall be
conclusively presumed to have been given, whether or not the Holder receives
such notice. In any case, failure to give such notice by mail or any defect in
the notice to the Holder of any Security designated for redemption in whole or
in part shall not affect the validity of the proceedings for the redemption of
any other Security.

         Section 3.4 Effect of Notice of Redemption. Once notice of redemption
is mailed in accordance with Section 3.3, Securities called for redemption
become due and payable on the Redemption Date and at the Redemption Price plus
accrued and unpaid interest, if any. Upon surrender to the Trustee or Paying
Agent, such Securities called for redemption shall be paid at the Redemption
Price (which shall include accrued interest thereon to the Redemption Date), but
installments of interest, the maturity of which is on or prior to the Redemption
Date, shall be payable to Holders of record at the close of business on the
relevant Record Dates.

                                      -38-

<PAGE>   43

         Section 3.5 Deposit of Redemption Price. On or before 11:00 a.m. New
York time on the Redemption Date, the Issuers shall deposit with the Paying
Agent U.S. Legal Tender sufficient to pay the Redemption Price plus accrued
interest, if any, of all Securities to be redeemed on that date.

         If the Issuers comply with the preceding paragraph, then, unless the
Issuers default in the payment of such Redemption Price plus accrued interest,
if any, interest on the Securities to be redeemed will cease to accrue on and
after the applicable Redemption Date, whether or not such Securities are
presented for payment.

         Section 3.6 Securities Redeemed in Part. Upon surrender of a Security
that is to be redeemed in part only, the Trustee shall upon written instruction
from the Issuers authenticate for the Holder a new Security or Securities in a
principal amount equal to the unredeemed portion of the Security surrendered.

         Section 3.7 Optional Redemption. (a) Except as provided in Section
3.7(b), the Securities will not be redeemable at the option of the Issuers prior
to February 1, 2005. On and after such date, the Securities will be redeemable,
at the Issuers' option, in whole or in part, at the following Redemption Prices
(expressed in percentages of principal amount), if redeemed during the 12-month
period commencing on February 1st of the years set forth below, plus accrued and
unpaid interest, if any, to the Redemption Date:

<TABLE>
<CAPTION>

Period                                                    Redemption
------                                                       Price
                                                             -----
<S>                                                      <C>
2005....................................................    106.375%
2006....................................................    104.250%
2007....................................................    102.125%
2008 and thereafter.....................................   100.0000%
</TABLE>

         (b) At any time, or from time to time, on or prior to February 3, 2003,
the Issuers may, at their option, use the net cash proceeds of one or more
Equity Offerings to redeem up to 35% of the aggregate principal amount of the
Securities issued pursuant to this Indenture at a Redemption Price equal to
112.750% of the principal amount thereof, plus accrued and unpaid interest
thereon, if any, to the date of redemption; provided, that after any such
redemption the aggregate principal amount of Securities outstanding must equal
at least 65% of the aggregate principal amount of the Securities theretofore
issued pursuant to this Indenture. In order to effect the foregoing redemption
with the net cash proceeds of any Equity Offering, the Issuers shall make such
redemption not more than 60 days after the consummation of any such Equity
Offering.

                                      -39-

<PAGE>   44

                                  ARTICLE FOUR

                                    COVENANTS

         Section 4.1 Payment of Securities. The Issuers shall pay the principal
of and interest on the Securities in the manner provided in the Securities. An
installment of principal of or interest on the Securities shall be considered
paid on the date it is due if the Trustee or Paying Agent holds on that date
U.S. Legal Tender designated for and sufficient to pay the installment. Interest
on the Securities will be computed on the basis of a 360-day year comprised of
twelve 30-day months.

         Section 4.2 Maintenance of Office or Agency. (a) The Issuers shall
maintain in the Borough of Manhattan, The City of New York, the office or agency
required under Section 2.3. The Issuers shall give prompt written notice to the
Trustee of the location, and any change in the location, of such office or
agency. If at any time the Issuers shall fail to maintain any such required
office or agency or shall fail to furnish the Trustee with the address thereof,
such presentations, surrenders, notices and demands may be made or served at the
address of the Trustee set forth in Section 13.2.

         (b) The Issuers may also from time to time designate one or more other
offices or agencies where the Securities may be presented or surrendered for any
or all such purposes and may from time to time rescind such designations. The
Issuers will give prompt written notice to the Trustee of any such designation
or rescission and of any change in the location of any such other office or
agency.

         (c) The Issuers hereby initially designate the Trustee located in the
Borough of Manhattan, The City of New York, as such office of the Issuers in
accordance with Section 2.3.

         Section 4.3 Limitation on Restricted Payments. (a) NATG shall not, and
shall not permit any of its Restricted Subsidiaries to directly or indirectly:
(A) declare or pay any dividend or make any distribution on or in respect of
shares of NATG's Capital Stock to holders of such Capital Stock (other than
dividends or distributions payable in Qualified Capital Stock of NATG), (B)
purchase, redeem or otherwise acquire or retire for value any Capital Stock of
NATG or any Capital Stock of any Subsidiary of NATG not held by an Issuer or
Subsidiary Guarantor, or any warrants, rights or options to purchase or acquire
shares of any class of any such Capital Stock, or declare or pay any dividend,
or make any distribution, on or in respect of any such Capital Stock, (C) make
any principal payment on, purchase, defease, redeem, prepay or otherwise acquire
or retire for value, prior to any scheduled final maturity, scheduled repayment
or scheduled sinking fund payment, any Subordinated Indebtedness, or (D) make
any Restricted Investment (each of the foregoing actions set forth in clauses
(A), (B), (C) and (D) being referred to as a "Restricted Payment"); provided,
that a Restricted Payment may be made, if at the time of such Restricted Payment
and immediately after giving effect thereto, (i) no Default or Event of Default
shall have occurred and be continuing, (ii) NATG is able to incur at least $1.00
of additional Indebtedness (other than Permitted Indebtedness) in compliance
with Section 4.4 and (iii) the aggregate amount of Restricted Payments
(including such proposed Restricted Payment) made subsequent to

                                      -40-
<PAGE>   45

December 31, 1999 (the amount expended for such purposes, if other than in cash,
being the fair market value of such property as determined reasonably and in
good faith by the Board of Directors of Parent) shall not exceed the sum of: (x)
50% of the cumulative Consolidated Net Income (or if cumulative Consolidated Net
Income shall be a loss, minus 100% of such loss) of NATG earned subsequent to
December 31, 1999 and through the last day of the fiscal quarter ending prior to
the date the Restricted Payment occurs (the "Reference Date") treating such
period as a single accounting period; plus (y) 100% of the aggregate net cash
proceeds of, or fair market value of property other than cash (determined in
good faith by the Board of NATG) constituting, any equity contribution received
by NATG from a holder of NATG's Capital Stock to the extent not required to be
used to repay Indebtedness under the Senior Secured Credit Agreement or redeem
Securities under this Indenture; plus (z) (1) the lesser of (I) 100% of the
aggregate amount of cash and/or fair market value of property other than cash
(as determined in good faith by the Board of Directors of Parent) received by an
Issuer or Subsidiary Guarantor from the disposition or sale of any Restricted
Investment (other than to a Subsidiary of Parent) that was made after the Issue
Date and (II) the initial amount of such Investment; plus (2) an amount equal to
the net reduction in Restricted Investments in Unrestricted Subsidiaries of NATG
resulting from dividends, repayments of loans or advances or other transfers of
assets, in each case to an Issuer or Subsidiary Guarantor from an Unrestricted
Subsidiary; plus (3) to the extent any Unrestricted Subsidiary of NATG is
redesignated as a Restricted Subsidiary, the lesser of (I) the amount of NATG's
initial Investment in such Unrestricted Subsidiary and (II) the fair market
value of NATG's investment in such Unrestricted Subsidiary as of the date of
such redesignation; provided, that no amount shall be included in this clause
(z) to the extent such amount is included in Consolidated Net Income of NATG.

                  (b) The provisions of paragraph (a) above do not, however,
prohibit: (1) the payment of any dividend or the consummation of any irrevocable
redemption within 60 days after the date of declaration of such dividend or
notice of such redemption if the dividend or redemption would have been
permitted on the date of declaration or notice; (2) the acquisition of any
Subordinated Indebtedness, either (i) solely in exchange for shares of Qualified
Capital Stock of Parent, (ii) through the application of net proceeds of a
substantially concurrent sale for cash (other than to a Restricted Subsidiary of
Parent) of shares of Qualified Capital Stock of Parent, or (iii) with the net
cash proceeds of Permitted Refinancing Indebtedness used to Refinance such
Subordinated Indebtedness; (3) so long as no Default or Event of Default shall
have occurred and be continuing, dividends or loans to Parent to enable Parent
to repurchase Junior Subordinated Notes and/or Capital Stock of Parent from
former or current employees, officers, directors or consultants of Parent or any
of its Subsidiaries or their authorized representatives upon the death,
disability or termination of employment of such Persons, in an amount not to
exceed $2.0 million in any calendar year; provided, that NATG may carry over and
make in a subsequent year, in addition to the amounts permitted for such fiscal
year, the amount of such dividends or loans permitted to have been made but not
made in any preceding fiscal year up to a maximum of $10.0 million in any fiscal
year; (4) so long as no Default or Event of Default shall have occurred and be
continuing, dividends or loans to Parent not to exceed $100,000 in any fiscal
year, to enable Parent to make payments to holders of its Capital Stock in lieu
of issuance of fractional shares of its Capital Stock; (5) dividends or loans to
Parent to enable Parent to repurchase, or the repurchase by NATG or a Restricted
Subsidiary of NATG, for cash pursuant to, and in compliance with, the Put/Call
Agreements certain shares of Parent Common Stock and Parent Preferred Stock
issued and

                                      -41-

<PAGE>   46

outstanding prior to the Issue Date; (6) dividends or loans to Parent in an
amount not to exceed $250,000 in any calendar year for the purpose of permitting
Parent to pay its ordinary operating expenses (including, without limitation,
directors' fees, indemnification obligations, professional fees and expenses);
(7) dividends or loans to Parent solely for the purpose of paying franchise
taxes, federal, state and local income taxes and interest and penalties with
respect thereto, if any, payable by Parent, provided, that any such income taxes
shall be attributable to income of NATG and its Restricted Subsidiaries; or (8)
so long as no Default or Event of Default shall have occurred and be continuing
or would occur as a consequence thereof, other Restricted Payments in an
aggregate amount not to exceed $7.5 million since the Issue Date.

         In determining the aggregate amount of Restricted Payments made
subsequent to the Issue Date in accordance with clause (iii) of the first
paragraph of this Section 4.3(a), amounts expended pursuant to clauses (1),
(2)(i), (2)(ii), (3), (4) and (6), in each case to the extent not duplicative of
amounts already included therein.

         (c) The amount of all Restricted Payments (other than an Investment
(which shall be valued as set forth in the definition thereof) and cash) shall
be the fair market value on the date of the Restricted Payment of the asset(s)
or securities proposed to be transferred or issued to or by NATG or such
Subsidiary, as the case may be, pursuant to the Restricted Payment. The fair
market value of any assets or securities that are required to be valued by this
Section 4.3 shall be determined by the Board of Directors of Parent whose
resolution with respect thereto shall be conclusive. The Board of Directors'
determination must be based upon an opinion or appraisal issued by an
Independent Financial Adviser if the fair market value exceeds $10.0 million.

         (d) Not later than the date of making any Restricted Payment, NATG
shall deliver to the Trustee an Officers' Certificate stating that such
Restricted Payment complies with this Indenture and setting forth in reasonable
detail the basis upon which the required calculations were computed, which
calculations may be based upon Parent's latest available internal quarterly
financial statements.

         Section 4.4 Limitation on Incurrence of Additional Indebtedness. NATG
shall not, and shall not permit any of its Restricted Subsidiaries to, directly
or indirectly, Incur any Indebtedness (other than Permitted Indebtedness);
provided, that if no Default or Event of Default shall have occurred and be
continuing at the time or as a consequence of the Incurrence of any such
Indebtedness, NATG or any Subsidiary Guarantor may Incur Indebtedness
(including, without limitation, Acquired Indebtedness), if on the date of the
Incurrence of such Indebtedness, after giving effect to the Incurrence thereof,
the Consolidated Fixed Charge Coverage Ratio is greater than 2.0 to 1.0 during
the period commencing on the Issue Date and ending January 31, 2002, 2.25 to 1.0
during the period commencing February 1, 2002 and ending January 31, 2004, and
2.5 to 1.0 thereafter; provided, further, that NATG shall not, and shall not
permit any of its Restricted Subsidiaries to, directly or indirectly, Incur any
Contingent Obligations in respect of any Junior Subordinated Notes.

         Section 4.5 Corporate Existence. Except as otherwise permitted by
Article Five, NATG shall do or cause to be done all things necessary to preserve
and keep in full force and effect its

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<PAGE>   47

limited liability company existence and the corporate, limited liability
company, partnership or other existence of each of its Restricted Subsidiaries
(including the Corporate Issuer) in accordance with the respective
organizational documents of each such Restricted Subsidiary and the rights
(charter and statutory) and material franchises of NATG and each of its
Restricted Subsidiaries; provided, that NATG shall not be required to preserve
any such right, franchise or corporate existence with respect to any Subsidiary
of an Issuer if the Board of Directors of Parent shall determine that the loss
thereof is not, and will not be, adverse in any material respect to the Holders;
and provided, further, that notwithstanding anything to the contrary in this
Indenture, the Issuers shall ensure that at all times at least one of the
Issuers or any co-issuer of the Securities is a corporation organized under the
laws of the United States or any state thereof or the District of Columbia.

         Section 4.6 Payment of Taxes and Other Claims. (a) NATG will, and will
cause each of its Restricted Subsidiaries to, pay all material taxes,
assessments and other governmental charges imposed upon it or any of its
properties or assets or in respect of any of its income, businesses or
franchises before any penalty, fine or interest accrues thereon, and all claims
(including, without limitation, claims for labor, services, materials and
supplies) for sums that have become due and payable and that by law have or may
become a Lien upon any of its properties or assets, prior to the time when any
penalty, fine or interest shall be incurred with respect thereto; provided, that
no such charge or claim need be paid if being contested in good faith by
appropriate proceedings promptly instituted and diligently conducted and if such
reserve or other appropriate provision, if any, with respect to any liability
for taxes, as shall be required in conformity with GAAP shall have been made
therefor in the financial statements of NATG or any of its Restricted
Subsidiaries.

         (b) NATG will not, and will not permit any of its Restricted
Subsidiaries to, file or consent to the filing of any consolidated income tax
return with any Person (other than Parent and its Restricted Subsidiaries).

         Section 4.7 Maintenance of Properties and Insurance. NATG will, and
will cause its Restricted Subsidiaries to, maintain or cause to be maintained in
good repair, working order and condition, ordinary wear and tear excepted, all
material properties used or useful in the business of NATG and its Restricted
Subsidiaries and from time to time will make or cause to be made all appropriate
repairs, renewals and replacements thereof. NATG will maintain or cause to be
maintained, with financially sound and reputable insurers, insurance with
respect to its properties and business and the properties and businesses of its
Restricted Subsidiaries against loss or damage (including, without limitation,
business interruption insurance) of the kinds customarily carried or maintained
under similar circumstances by corporations of established reputation engaged in
similar businesses.

         Section 4.8 Compliance Certificate; Notice of Default. (a) Each Issuer
shall deliver to the Trustee, within 120 days after the close of each fiscal
year an Officers' Certificate stating that a review of the activities of such
Issuer has been made under the supervision of the signing Officers with a view
to determining whether it has kept, observed, performed and fulfilled its
obligations under this Indenture and further stating, as to each such Officer
signing such

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<PAGE>   48

certificate, that to the best of such Officer's knowledge, such Issuer during
such preceding fiscal year has kept, observed, performed and fulfilled each and
every such covenant and no Default or Event of Default occurred during such year
and at the date of such certificate there is no Default or Event of Default that
has occurred and is continuing or, if such signers do know of such Default or
Event of Default, the certificate shall describe its status with particularity.
The Officers' Certificate shall also notify the Trustee should the Issuers elect
to change the manner in which it fixes its fiscal year end.

         (b) So long as not contrary to the recommendations of the American
Institute of Certified Public Accountants, the annual financial statements
delivered pursuant to Section 4.10 shall be accompanied by a written report of
the Issuers' independent accountants (who shall be a firm of established
national reputation) that in conducting their audit of such financial statements
nothing has come to their attention that would lead them to believe that the
Issuers have violated any provisions of Article Four, Five or Six of this
Indenture insofar as they relate to accounting matters or, if any such violation
has occurred, specifying the nature and period of existence thereof, it being
understood that such accountants shall not be liable directly or indirectly to
any Person for any failure to obtain knowledge of any such violation.

         (c) Each Issuer shall deliver to the Trustee, forthwith upon becoming
aware of any Default or Event of Default in the performance of any covenant,
agreement or condition contained in this Indenture, an Officers' Certificate
specifying the Default or Event of Default and describing its status with
particularity.

         Section 4.9 Compliance with Laws. NATG shall comply, and shall cause
each of its Restricted Subsidiaries to comply, with all applicable statutes,
rules, regulations, orders and restrictions of the United States, all states and
municipalities thereof, and of any governmental department, commission, board,
regulatory authority, bureau, agency and instrumentality of the foregoing, in
respect of the conduct of their respective businesses and the ownership of their
respective properties, except for such noncompliances as would not in the
aggregate have a material adverse effect on the financial condition or results
of operations of NATG and its Restricted Subsidiaries taken as a whole.

         Section 4.10 Reports to Holders. (a) Whether or not required by the
rules and regulations of the SEC, so long as any Securities are outstanding,
Parent and the Issuers shall furnish the Holders of Securities:

                  (1) all quarterly and annual financial information that would
         be required to be contained in a filing with the SEC on Forms 10-Q and
         10-K if Parent or the Issuers were required to file such Forms,
         including a "Management's Discussion and Analysis of Financial
         Condition and Results of Operations" that describes the financial
         condition and results of operations of Parent and its consolidated
         Subsidiaries (or, if Parent shall cease to own more than a majority of
         the Voting Securities of NATG, of NATG and its consolidated
         subsidiaries) (showing in the case of Parent's financial statements, in
         reasonable detail, either on the face of the financial statements or in
         the footnotes thereto, the information required to be presented with
         respect to the Issuers and the Guarantors under Staff

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<PAGE>   49

         Accounting Bulletin 53 or any successor interpretation or rule of the
         SEC with respect thereto) and, with respect to the annual information
         only, a report thereon by the certified independent accountants of
         Parent and its consolidated subsidiaries (or, if Parent shall cease to
         own more than a majority of the Voting Securities of NATG, of NATG and
         its consolidated subsidiaries), in each case, within five days after
         the time specified in the rules and regulations of the SEC;

                  (2) all current reports that would be required to be filed
         with the SEC on Form 8-K if Parent or the Issuers were required to file
         such reports, in each case within two days after the time periods
         specified in the SEC's rules and regulations.

         (b) Following the consummation of the exchange offer contemplated by a
Registration Rights Agreement, whether or not required by the rules and
regulations of the SEC, Parent or NATG will file a copy of all such information
and reports with the SEC for public availability within the time periods
specified in the SEC's rules and regulations (unless the SEC will not accept
such a filing) and make such information available to securities analysts and
prospective investors upon request. In addition, for so long as any Securities
remain outstanding, NATG shall furnish to the Holders and to securities analysts
and prospective investors, upon their request, the information required to be
delivered pursuant to Rule 144A(d)(4) under the Securities Act. Parent and the
Issuers will also comply with the other provisions of TIA ss.314(a).

         Section 4.11 Waiver of Stay, Extension or Usury Laws. Each of the
Issuers and each Guarantor covenants (to the extent that it may lawfully do so)
that it will not at any time insist upon, plead, or in any manner whatsoever
claim or take the benefit or advantage of, any stay or extension law or any
usury law or other law that would prohibit or forgive such Issuer or Guarantor
from paying all or any portion of the principal of and/or interest on the
Securities or the Guarantee of any such Guarantor as contemplated herein,
wherever enacted, now or at any time hereafter in force, or which may affect the
covenants or the performance of this Indenture, and (to the extent that it may
lawfully do so) each hereby expressly waives all benefit or advantage of any
such law, and covenants that it will not hinder, delay or impede the execution
of any power herein granted to the Trustee, but will suffer and permit the
execution of every such power as though no such law had been enacted.

         Section 4.12 Limitations on Transactions with Affiliates. (a) NATG
shall not, and shall not permit any of its Restricted Subsidiaries to, directly
or indirectly, enter into or permit to exist any transaction (including, without
limitation, the purchase, sale, lease or exchange of any property or the
rendering of any service) with or for the benefit of any Affiliate (each an
"Affiliate Transaction") other than (i) Affiliate Transactions permitted under
the following paragraph and (ii) Affiliate Transactions on terms that are no
less favorable to NATG or such Restricted Subsidiary, as the case may be, than
those that might reasonably have been obtained in a comparable transaction at
such time on an arm's-length basis from a Person that is not an Affiliate of
NATG or such Restricted Subsidiary. All Affiliate Transactions (and each series
of related Affiliate Transactions which are similar or part of a common plan)
involving aggregate payments or other property with a fair market value in
excess of $2.5 million shall be approved by the Board of Directors of NATG or
such Restricted Subsidiary, as the case may be, such approval to be

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<PAGE>   50

evidenced by a resolution stating that such Board of Directors has determined
that such transaction complies with the foregoing provisions. If NATG or any
such Restricted Subsidiary enters into an Affiliate Transaction (or a series of
related Affiliate Transactions related to a common plan) that involves an
aggregate fair market value of more than $10.0 million, NATG or such Restricted
Subsidiary, as the case may be, shall, prior to the consummation thereof, obtain
an opinion that the Affiliate Transaction complies with the requirements of this
covenant from an Independent Financial Advisor and file the same with the
Trustee.

         (b) The restrictions set forth in paragraph (a) shall not apply to: (i)
reasonable fees and compensation paid to and indemnity provided on behalf of,
officers, directors, employees, agents or consultants of Parent, NATG or any
Restricted Subsidiaries of NATG as determined in good faith by Parent's Board of
Directors or senior officers; (ii) transactions exclusively between or among any
of NATG or any Restricted Subsidiaries of NATG; provided, that such transactions
are not otherwise prohibited by this Indenture; (iii) any agreement as in effect
as of the Issue Date or any amendment thereto or any transaction contemplated
thereby (including pursuant to any amendment thereto) in any replacement
agreement thereto so long as any such amendment or replacement agreement is not
more disadvantageous to NATG or its Subsidiaries, as the case may be, in any
material respect, than the original agreement as in effect on the Issue Date;
(iv) Restricted Payments permitted under Section 4.3; (v) any issuance of
securities or other payments, awards or grants in cash, securities or otherwise
pursuant to, or the funding of, employment arrangements, stock options and stock
ownership plans of Parent entered into in the ordinary course of business and
approved by Parent's Board of Directors; (vi) the payment of reasonable and
customary management, consulting and advisory fees and related out of pocket
expenses of WSP and its Affiliates, including, without limitation, in connection
with acquisitions, divestitures, or financings by Parent or any of its
Restricted Subsidiaries, in each case as may be approved by the Board of
Directors of Parent in good faith; (vii) loans and advances to employees and
officers of Parent and its Restricted Subsidiaries in the ordinary course of
business for bona fide business purposes not in excess of $1.0 million at any
time outstanding; (viii) indemnification agreements provided for the benefit of
Parent or any Restricted Subsidiary of Parent from officers, directors,
employees agents or consultants of Parent or any Restricted Subsidiary of
Parent; (ix) transactions effected as part of a Qualified Receivables
Transaction; and (x) the payment to Jack Reich for consulting services pursuant
to his consulting agreement with Parent and its Subsidiaries as in effect as of
the Issue Date or any amendment thereto or any transaction contemplated thereby
(including pursuant to any amendment thereto) in any replacement agreement
thereto so long as any such amendment or replacement agreement is not more
disadvantageous to Parent or its Subsidiaries, as the case may be, in any
material respect than the original agreement as in effect on the Issue Date.

         Section 4.13 Limitation on Dividend and Other Payment Restrictions
Affecting Restricted Subsidiaries. NATG shall not, and shall not permit any of
its Restricted Subsidiaries to, directly or indirectly, create or permit to
exist or become effective any encumbrance or restriction on the ability of any
Restricted Subsidiary of NATG to: (a) pay dividends or make any other
distributions on or in respect of its Capital Stock; (b) make loans or advances
to pay any Indebtedness or other obligation owed to any Issuer or Subsidiary
Guarantor; or (c) transfer any of its property or assets to any Issuer or
Subsidiary Guarantor, except for such encumbrances or restrictions existing
under or by reason of: (1) applicable law, regulations or orders of any

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<PAGE>   51

governmental or judicial authority; (2) this Indenture, the Securities, the
Guarantees, or the Senior Secured Credit Agreement to the extent Incurred in
accordance with this Indenture; (3) customary non-assignment provisions of any
contract or any lease governing a leasehold interest of NATG or any Restricted
Subsidiary of NATG; (4) agreements existing on the Issue Date to the extent and
in the manner such agreements are in effect on the Issue Date; (5) any
restriction or encumbrance contained in contracts for sale of assets permitted
by this Indenture in respect of the assets being sold pursuant to such contracts
pending the close of such sale, which encumbrance or restriction is not
applicable to any asset other than the asset being sold pursuant to such
contract; (6) Purchase Money Obligations for property acquired in the ordinary
course of business that impose restrictions of the nature described in clause
(c) above on the property so acquired; (7) restrictions of the nature described
in clause (c) above on the transfer of assets subject to any Lien permitted
under this Indenture imposed by the holder of such Lien; (8) any instrument
governing Indebtedness or Capital Stock of a Person acquired by NATG or any of
its Restricted Subsidiaries as in effect at the time of such acquisition (except
to the extent such Indebtedness or Capital Stock was incurred in connection with
or in contemplation of such acquisition), which encumbrance or restriction is
not applicable to any Person, or the properties or assets of any Person, other
than the Person, or the property or assets of the Person, so acquired; provided,
that, in the case of Indebtedness, such Indebtedness was permitted by the terms
of this Indenture to be incurred; (9) provisions with respect to the disposition
or distribution of assets or property in joint venture agreements, asset sale
agreements, stock sale agreements and other similar agreements entered into in
the ordinary course of business; (10) any encumbrance or restriction on a
Receivables Entity effected in connection with a Qualified Receivables
Transaction; (11) restrictions on cash or other deposits or net worth imposed by
customers under contracts entered into in the ordinary course of business; or
(l2) an agreement governing Indebtedness incurred to refinance the Indebtedness
issued, assumed or incurred pursuant to an agreement referred to in clause (b)
or (d) above; provided, that the provisions relating to such encumbrance or
restriction contained in any such Indebtedness are no less favorable to the
Issuers or Subsidiary Guarantors in any material respect as determined by the
Board of Directors of Parent in its reasonable and good faith judgment than the
provisions relating to such encumbrance or restriction contained in agreements
referred to in such clause (b) or (d).

`         Section 4.14 Limitation on Liens. NATG shall not, and shall not permit
any of its Restricted Subsidiaries to, directly or indirectly, create, incur,
assume or permit to exist any Lien on or with respect to any property or asset
of any kind (including any document or instrument in respect of goods or
accounts receivable) of NATG or any of its Restricted Subsidiaries, whether now
owned or hereafter acquired, or any income or profits therefrom, or file or
permit the filing of, or permit to remain in effect, any financing statement or
other similar notice of any Lien with respect to any such property, asset,
income or profits under the Uniform Commercial Code of any state or under any
similar recording or notice statute, unless, (i) in the case of Liens securing
Subordinated Indebtedness, the Securities and Guarantees are secured by a Lien
on such property, assets or proceeds that is senior in priority to such Liens
and (ii) in all other cases, the Securities and Guarantees are equally and
ratably secured. Notwithstanding the foregoing, this Section 4.14 shall not
prohibit or apply to (A) Liens securing the Senior Secured Credit Agreement; (B)
Liens securing Senior Debt and Liens securing Guarantor Senior Debt; (C) Liens
securing the Securities and the Guarantees; (D) Liens of an Issuer or Subsidiary
Guarantor on assets of any other Issuer or Subsidiary Guarantor; and (E)
Permitted Liens.

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<PAGE>   52

         Section 4.15 Change of Control. (a) Upon the occurrence of a Change of
Control, the Issuers shall be obligated to make an offer to purchase (the
"Change of Control Offer"), and shall purchase, on a Business Day (the "Change
of Control Payment Date") as described below, all of the then outstanding
Securities at a purchase price equal to 101% of the principal amount thereof,
plus accrued and unpaid interest, if any, thereon to the Change of Control
Payment Date. The Change of Control Offer shall remain open for at least 20
Business Days and until the close of business on the Change of Control Payment
Date.

         (b) Prior to the mailing of the notice referred to below, but in any
event within 30 days following any Change of Control, each Issuer covenants to
(i) repay in full all Indebtedness under the Senior Secured Credit Agreement and
all other Senior Debt the terms of which require repayment upon a Change of
Control or offer to repay in full all Indebtedness under the Credit Agreement
and all other such Senior Debt and to repay the Indebtedness owed to each lender
which has accepted such offer or (ii) obtain the requisite consents under the
Senior Secured Credit Agreement and all other Senior Debt to permit the
repurchase of the Securities as provided below. An Issuer shall first comply
with the covenant in the immediately preceding sentence before it shall be
required to repurchase Securities pursuant to the provisions described below. An
Issuer's failure to comply with the covenant described in the second preceding
sentence (and any failure to send the notice referred to in clause (c) below
because same is prohibited by the second preceding sentence) may (with notice
and lapse of time) constitute an Event of Default described in clause (c) of
Section 6.1 but shall not constitute an Event of Default described in clause (b)
of Section 6.1.

         (c) Within 30 days following the date upon which a Change of Control
occurs (the "Change of Control Date"), the Issuers shall send, by first class
mail, a notice to each Holder, with a copy to the Trustee, which notice shall
govern the terms of the Change of Control Offer. The notice to the Holders shall
contain all instructions and materials necessary to enable such Holders to
tender Securities pursuant to the Change of Control Offer. Such notice shall
state:

                  (1) that the Change of Control Offer is being made pursuant to
         this Section 4.15 and that all Securities tendered and not withdrawn
         will be accepted for payment;

                  (2) the purchase price (including the amount of accrued
         interest) and the Change of Control Payment Date, which shall be a
         Business Day, that is not earlier than 30 days or later than 45 days
         from the date such notice is mailed;

                  (3) that any Security not tendered will continue to accrue
         interest;

                  (4) that, unless the Issuers default in making payment
         therefor, any Security accepted for payment pursuant to the Change of
         Control Offer shall cease to accrue interest after the Change of
         Control Payment Date;

                  (5) that Holders electing to have a Security purchased
         pursuant to a Change of Control Offer will be required to surrender the
         Security, with the form entitled "Option of Holder to Elect Purchase"
         on the reverse of the Security completed, to the Paying Agent

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<PAGE>   53

         at the address specified in the notice prior to the close of business
         on the third Business Day prior to the Change of Control Payment Date;

                  (6) that Holders will be entitled to withdraw their election
         if the Paying Agent receives, not later than the second Business Day
         prior to the Change of Control Payment Date, a telegram, telex,
         facsimile transmission or letter setting forth the name of the Holder,
         the principal amount of the Securities the Holder delivered for
         purchase and a statement that such Holder is withdrawing his election
         to have such Security purchased;

                  (7) that Holders whose Securities are purchased only in part
         will be issued new Securities in a principal amount equal to the
         unpurchased portion of the Securities surrendered; and

                  (8) the circumstances and relevant facts regarding such Change
         of Control.

         (d) On or before the Change of Control Payment Date, the Issuers shall
(i) accept for payment Securities or portions thereof tendered pursuant to the
Change of Control Offer, (ii) deposit with the Paying Agent U.S. Legal Tender
sufficient to pay the purchase price plus accrued interest, if any, of all
Securities so tendered and (iii) deliver to the Trustee Securities so accepted
together with an Officers' Certificate stating the Securities or portions
thereof being purchased by the Issuers. The Paying Agent shall promptly mail to
the Holders of Securities so accepted payment in an amount equal to the purchase
price plus accrued interest, if any, and upon written order of the Issuers the
Trustee shall promptly authenticate and mail to such Holders new Securities
equal in principal amount to any unpurchased portion of the Securities
surrendered. Any Securities not so accepted shall be promptly mailed by the
Issuers to the Holder thereof. For purposes of this Section 4.15, the Trustee
shall act as the Paying Agent.

         (e) Any amounts remaining with the Paying Agent after the purchase of
Securities pursuant to a Change of Control Offer shall be returned by the
Trustee to the Issuers.

         (f) The Issuers intend to comply with the requirements of Rule 14e-1
under the Exchange Act to the extent such laws and regulations are applicable in
connection with the repurchase of Securities pursuant to a Change of Control
Offer. To the extent the Issuers comply with the provisions of any such
securities laws or regulations, the Issuers will not be deemed to have breached
their obligations under the provisions of this Section 4.15.

         Section 4.16 Limitation on Asset Sales. (a) NATG shall not, and shall
not permit any of its Restricted Subsidiaries to, consummate an Asset Sale,
unless (i) NATG or the applicable Restricted Subsidiary, as the case may be,
receives consideration at the time of such Asset Sale which, taken as a whole,
is at least equal to the fair market value of the assets sold or otherwise
disposed of (as determined in good faith, by Parent's Board of Directors); (ii)
at least 75% of the consideration received by the Issuers or the Restricted
Subsidiary, as the case may be, from such Asset Sale is received at the time of
the disposition and consists of one of the following: (a) cash or Cash
Equivalents; (b) any liabilities (as shown on NATG's or such Restricted
Subsidiary's most recent balance sheet) of NATG or any such Restricted
Subsidiary (other than liabilities that are by their terms subordinated to the
Securities) that are assumed by the transferee of any such assets, (c)

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<PAGE>   54

any securities, notes or other obligations received by NATG or any such
Subsidiary from such transferee that are converted by NATG or any such
Subsidiary into cash within 180 days after such Asset Sale (to the extent of the
cash received); and (d) any combination of the foregoing; (iii) upon the
consummation of an Asset Sale, NATG shall apply, or cause such Restricted
Subsidiary to apply, the Net Cash Proceeds relating to such Asset Sale within
365 days of receipt thereof either (A) to prepay any Senior Debt or Guarantor
Senior Debt and, in the case of any Senior Debt or Guarantor Senior Debt under
any revolving credit facility, effect a permanent reduction in the availability
under such revolving credit facility; provided, that no such permanent reduction
in availability need be made prior to December 15, 2001 to the extent that the
Senior Debt being repaid had been borrowed under the acquisition subfacility of
the revolving credit facility under the Senior Secured Credit Agreement and/or
(B) to invest in or to acquire other properties and assets that replace the
properties and assets that were the subject of such Asset Sale or in properties
and assets that will be used or useful in a Permitted Business ("Replacement
Assets") and/or (C) to acquire all or substantially all of the assets of, or all
of the voting stock of, another Person engaged in a Permitted Business;
provided, that if voting stock is acquired, such Person becomes a Subsidiary
Guarantor; provided, that NATG may not sell or otherwise dispose of any Capital
Stock of the Corporate Issuer except in compliance with Section 5.1. Pending the
final application of any Net Cash Proceeds, NATG or such Restricted Subsidiary
may temporarily reduce revolving credit borrowings or otherwise invest such Net
Cash Proceeds in any manner that is not otherwise prohibited by this Indenture.
On the 366th day after an Asset Sale or such earlier date, if any, as the senior
management or Board of Directors, as the case may be, of NATG or such Restricted
Subsidiary determines not to apply the Net Cash Proceeds relating to such Asset
Sale as set forth in clause (iii) of the preceding paragraph (each, a "Net
Proceeds Offer Trigger Date"), such aggregate amount of Net Cash Proceeds which
has not been applied on or before such Net Proceeds Offer Trigger Date as
permitted in clause (iii) of the next preceding sentence (each a "Net Proceeds
Offer Amount") shall be applied by NATG or such Restricted Subsidiary to make an
offer to purchase (the "Net Proceeds Offer") on a date (the "Net Proceeds Offer
Payment Date") not less than 30 nor more than 60 days following the applicable
Net Proceeds Offer Trigger Date, from all Holders on a pro rata basis, that
principal amount of Securities equal to the Net Proceeds Offer Amount at a price
equal to 100% of the principal amount of the Securities to be purchased, plus
accrued and unpaid interest thereon, if any, to the date of purchase; provided,
that if at any time any non-cash consideration received by NATG or any such
Restricted Subsidiary, as the case may be, in connection with any Asset Sale is
converted into or sold or otherwise disposed of for cash (other than interest
received with respect to any such non-cash consideration), then such conversion
or disposition shall be deemed to constitute an Asset Sale hereunder and the Net
Cash Proceeds thereof shall be applied in accordance with this covenant. The
Issuers may defer the Net Proceeds Offer until there is an aggregate unutilized
Net Proceeds Offer Amount equal to or in excess of $10.0 million resulting from
one or more Asset Sales (at which time, the entire unutilized Net Proceeds Offer
Amount, and not just the amount in excess of $10.0 million, shall be applied as
required pursuant to this paragraph).

         (b) In the event of the transfer of substantially all (but not all) of
the property and assets of NATG and its Restricted Subsidiaries as an entirety
to a Person in a transaction permitted under the covenant described under
Section 5.1. hereof, the successor corporation shall be deemed to have sold the
properties and assets of NATG and its Subsidiaries not so transferred for
purposes of this

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<PAGE>   55

covenant, and shall comply with the provisions of this covenant with respect to
such deemed sale as if it were an Asset Sale. In addition, the fair market value
of such properties and assets of NATG or such Subsidiaries deemed to be sold
pursuant to this paragraph less the fair market value of all liabilities of such
Person related to such property and assets not transferred shall be deemed to be
Net Cash Proceeds for purposes of this covenant.

         (c) Notwithstanding the foregoing provisions of this covenant, NATG and
its Restricted Subsidiaries will be permitted to consummate an Asset Sale
without complying with such clauses to the extent that: (1) at least 75% of the
consideration for such Asset Sale constitutes Replacement Assets; and (2) such
Asset Sale is for fair market value as determined in good faith by the Board of
Directors of Parent; provided, that any consideration not constituting
Replacement Assets received by NATG or any of its Restricted Subsidiaries in
connection with any Asset Sale permitted to be consummated under this clause (c)
shall constitute Net Cash Proceeds subject to the provisions the foregoing
provisions of this covenant.

         (d) Notice of each Net Proceeds Offer shall be mailed or caused to be
mailed, by first class mail, by NATG or the relevant Subsidiary within 30 days
following the applicable Net Proceeds Offer Trigger Date to all Holders at their
last registered addresses, with a copy to the Trustee. A Net Proceeds Offer
shall remain open for a period of 20 Business Days or such longer period as may
be required by law. The notice shall contain all instructions and materials
necessary to enable such Holders to tender Securities pursuant to the Net
Proceeds Offer and shall comply with the procedures set forth in this Indenture.
To the extent that the aggregate amount of Securities tendered is less than the
Net Proceeds Offer Amount, NATG or the relevant Restricted Subsidiary may use
the remaining Net Proceeds Offer Amount for general corporate purposes or for
any other purpose not prohibited by this Indenture, and any such remaining Net
Cash Proceeds shall thereafter be deemed not to constitute Net Cash Proceeds.

         (e) NATG and its Restricted Subsidiaries intend to comply with the
requirements of Rule 14e-1 under the Exchange Act to the extent such laws and
regulations are applicable in connection with the repurchase of Securities
pursuant to a Net Proceeds Offer. To the extent that the provisions of any
securities laws or regulations conflict with the provisions of this covenant,
NATG and its Restricted Subsidiaries shall comply with the applicable securities
laws and regulations and shall not be deemed to have breached their obligations
under this covenant by virtue thereof.

         Section 4.17 Prohibition on Incurrence of Senior Subordinated Debt.
NATG shall not, and shall not permit any of its Restricted Subsidiaries to,
directly or indirectly, Incur any Indebtedness (other than the Securities and
the Guarantees and Indebtedness owed to an Issuer or a Wholly Owned Restricted
Subsidiary of an Issuer) that is by its terms (or by the terms of any agreement
governing such Indebtedness) subordinated in right of payment to any other
Indebtedness of such Person unless such Indebtedness (i) is Incurred by an
Issuer or Subsidiary Guarantor and (ii) is by its terms (or by the terms of any
agreement governing such Indebtedness) made expressly subordinate to the
obligations of such Issuer or Subsidiary Guarantor under this Indenture, the
Securities (in the case of an Issuer) and the Guarantees (in the case of a
Subsidiary

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<PAGE>   56

Guarantor) to the same extent and in the same manner as such obligations are
subordinated to Senior Debt or Guarantor Senior Debt, as applicable.

         Section 4.18 Additional Subsidiary Guarantees. (a) NATG will cause any
Subsidiary of NATG that after the Issue Date first becomes a guarantor of an
Issuer's obligations under the Senior Secured Credit Agreement to, within 10
days of the date on which it became such a guarantor (i) execute and deliver to
the Trustee a supplemental indenture in form reasonably satisfactory to the
Trustee pursuant to which such Subsidiary shall unconditionally guarantee all of
the Issuers' obligations under the Securities and this Indenture on the terms
set forth in this Indenture and (ii) deliver to the Trustee an Opinion of
Counsel that such supplemental indenture has been duly authorized, executed and
delivered by such Subsidiary and constitutes a legal, valid, binding and
enforceable obligation of such Subsidiary. Thereafter, such Subsidiary shall be
a Guarantor for all purposes of this Indenture.

         (b) In the event that the Senior Secured Credit Agreement shall no
longer be in effect, NATG shall cause any Domestic Restricted Subsidiary of
NATG, other than a Receivables Entity or a Restricted Subsidiary that is already
a Guarantor, to promptly (i) execute and deliver to the Trustee a supplemental
indenture in form reasonably satisfactory to the Trustee pursuant to which such
Subsidiary shall unconditionally guarantee all of the Issuers' obligations under
the Securities and this Indenture on the terms set forth in this Indenture and
(ii) deliver to the Trustee an Opinion of Counsel that such supplemental
indenture has been duly authorized, executed and delivered by such Subsidiary
and constitutes a legal, valid, binding and enforceable obligation of such
Subsidiary. Thereafter, such Subsidiary shall be a Guarantor for all purposes of
this Indenture.

         Section 4.19 Conduct of Business. (a) NATG shall not, and shall not
permit any of its Restricted Subsidiaries to, engage in any business other than
Permitted Businesses.

         (b) The Corporate Issuer shall engage in no business other than the
issuance of the Securities. Notwithstanding the foregoing, the Corporate Issuer
may engage in those activities that are incidental to (i) the maintenance of is
corporate existence in compliance with applicable law, (ii) legal, tax and
accounting matters in connection with any of the foregoing activities and (iii)
entering into, and performing its obligations under, the Documents to which it
is a party.

         Section 4.20 Disposal of Subsidiary Stock. Except for any sale of 100%
of the Capital Stock or other equity securities of a Restricted Subsidiary
effected in compliance with Section 4.3 and Section 5.1, NATG will not, and will
not permit any of its Restricted Subsidiaries to, directly or indirectly sell,
assign, pledge or otherwise encumber or dispose of any shares of Capital Stock
or other equity securities of any Restricted Subsidiary of NATG, except (1) to
qualify directors if required by applicable law, (2) to an Issuer or Subsidiary
Guarantor, and (3) Liens in favor of the lenders under the Senior Secured Credit
Agreement.

         Section 4.21 Payments for Consent. NATG will not, and will not permit
any of its Subsidiaries to, directly or indirectly, pay or cause to be paid any
consideration to or for the benefit of any Holder of Securities for or as an
inducement to any consent, waiver or amendment of any of the terms or provisions
of this Indenture or the Securities unless such consideration is offered to be

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<PAGE>   57

paid and is paid to all Holders of the Securities that consent, waive or agree
to amend in the time frame set forth in the solicitation documents relating to
such consent, waiver or agreement.

         Section 4.22 Maintenance of Separate Identity. Parent and NATG shall
take all actions required to maintain NATG's status and the status of NATG's
Restricted Subsidiaries as separate legal entities from Parent, including,
without limitation; (i) not holding NATG or its Restricted Subsidiaries out to
third parties as other than entities with assets and liabilities distinct from
Parent and Parent's other subsidiaries; (ii) not holding Parent out to be
responsible for the debts of NATG or NATG's Restricted Subsidiaries or, other
than by reason of owning Voting Securities of NATG, for any decisions or actions
relating to NATG; (iii) taking such other actions as are necessary on Parent's
part to ensure that all corporate procedures required by Parent's and NATG's
respective certificates of incorporation or of formation, as applicable, and
by-laws, if applicable, are duly and validly taken; (iv) keeping correct and
complete records and books of accounting and corporate minutes; and (v) not
acting in any manner that could foreseeably mislead others with respect to
NATG's and NATG's Restricted Subsidiaries separate identities.

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<PAGE>   58

                                  ARTICLE FIVE

                              SUCCESSOR CORPORATION

         Section 5.1 Merger, Consolidation and Sale of Assets. (a) No Issuer
shall, in a single transaction or series of related transactions, consolidate or
merge with or into any Person, or sell, assign, transfer, lease, convey or
otherwise dispose of (or cause or permit any Restricted Subsidiary of such
Issuer to sell, assign, transfer, lease, convey or otherwise dispose of) all or
substantially all of the assets of such Issuer and its Restricted Subsidiaries
(determined on a consolidated basis for such Issuer and its Restricted
Subsidiaries) whether as an entirety or substantially as an entirety to any
Person unless: (i) either (1) such Issuer shall be the surviving or continuing
corporation or (2) the Person (if other than such Issuer) formed by such
consolidation or into which such Issuer is merged or the Person which acquires
by sale, assignment, transfer, lease, conveyance or other disposition the
properties and assets of such Issuer and its Restricted Subsidiaries
substantially as an entirety (for purposes of this paragraph, the "Surviving
Entity") (x) shall be a corporation, partnership, trust or a limited liability
company organized and validly existing under the laws of the United States or
any State thereof or the District of Columbia and (y) shall expressly assume, by
supplemental indenture (in form and substance satisfactory to the Trustee),
executed and delivered to the Trustee, the due and punctual payment of the
principal of, and premium, if any, and interest on all of the Securities and the
performance of every covenant of the Securities, this Indenture and the
Registration Rights Agreement on the part of such Issuer to be performed or
observed; (ii) immediately after giving effect to such transaction and the
assumption contemplated by clause (i)(2)(y) above (including giving effect to
any Indebtedness and Acquired Indebtedness incurred or anticipated to be
incurred in connection with or in respect of such transaction), such Issuer or
such Surviving Entity, as the case may be, shall be able to incur at least $1.00
of additional Indebtedness (other than Permitted Indebtedness) pursuant to
Section 4.4; (iii) immediately before and immediately after giving effect to
such transaction and the assumption contemplated by clause (1)(ii)(y) above
(including, without limitation, giving effect to any Indebtedness and Acquired
Indebtedness incurred or anticipated to be incurred and any Lien granted in
connection with or in respect of the transaction), no Default or Event of
Default shall have occurred or be continuing; and (iv) such Issuer or Surviving
Entity, as the case may be, shall have delivered to the Trustee an Officers'
Certificate and an Opinion of Counsel, each stating that such consolidation,
merger, sale, assignment, transfer, lease, conveyance or other disposition and,
if a supplemental indenture is required in connection with such transaction,
such supplemental indenture comply with the applicable provisions of this
Indenture and that all conditions precedent in this Indenture relating to such
transaction have been satisfied. Notwithstanding the foregoing, the merger of an
Issuer with an Affiliate incorporated solely for the purpose of reincorporating
or similarly reorganizing such in another jurisdiction shall be permitted.

         (b) For purposes of the foregoing paragraph (a), the transfer (by
lease, assignment, sale or otherwise, in a single transaction or series of
transactions) of all or substantially all of the properties or assets of one or
more Restricted Subsidiaries of an Issuer the Capital Stock of which constitutes
all or substantially all of the properties and assets of such Issuer, shall be
deemed to be the transfer of all or substantially all of the properties and
assets of such Issuer.

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<PAGE>   59

         (c) Each Guarantor (other than any Guarantor whose Guarantee is to be
released in accordance with the terms of the Guarantee and this Indenture in
connection with any transaction complying with Section 4.16 shall not, and NATG
shall not cause or permit any Guarantor to, consolidate with or merge with or
into any Person unless: (i) the entity formed by or surviving any such
consolidation or merger (if other than such Guarantor) is a corporation,
partnership, trust or limited liability company organized and existing under the
laws of the United States or any State thereof or the District of Columbia; (ii)
such entity assumes by supplemental indenture all of the obligations of such
Guarantor under this Indenture and on its Guarantee; (iii) immediately after
giving effect to such transaction, no Default or Event of Default shall have
occurred and be continuing; and (iv) immediately after giving effect to such
transaction and the use of any net proceeds therefrom on a pro forma basis,
Parent could satisfy the provisions of clause (ii) of paragraph (a) of this
Section 5.1. Any merger or consolidation of a Guarantor with and into an Issuer
(with such Issuer being the surviving entity) or a Guarantor that is a Wholly
Owned Subsidiary of an Issuer need only comply with clause (iv) of paragraph (a)
of this Section 5.1.

         (d) Notwithstanding anything to the contrary in this Section 5.1, no
transaction shall be permitted under this Section 5.1 unless after giving effect
thereto, there shall be a co-issuer of the Securities that is a corporation
organized and existing under the laws of the United States or any State thereof
or the District of Columbia.

         Section 5.2 Successor Corporation Substituted. Upon any consolidation,
combination or merger or any transfer of all or substantially all of the assets
of an Issuer in accordance with Section 5.1 in which such Issuer is not the
continuing corporation, the successor Person formed by such consolidation or
into which such Issuer is merged or to which such conveyance, lease or transfer
is made shall succeed to, and be substituted for, and may exercise every right
and power of, such Issuer under this Indenture and the Securities with the same
effect as if such Surviving Entity had been named as such.

                                   ARTICLE SIX

                              DEFAULT AND REMEDIES

         Section 6.1 Events of Default. Each of the following shall be an "Event
of Default":

         (a) the failure to pay interest on any Securities when the same becomes
due and payable and the default continues for a period of 30 days (whether or
not such payment shall be prohibited by Article Ten or Article Twelve of this
Indenture);

         (b) the failure to pay the principal on any Securities, when such
principal becomes due and payable, at maturity, upon redemption or otherwise
(including the failure to make a payment to purchase Securities tendered
pursuant to a Change of Control Offer or a Net Proceeds Offer on the date
specified for such payment in the applicable offer to purchase) (whether or not
such payment shall be prohibited by Article Ten or Article Twelve of this
Indenture);

         (c) a default in the observance or performance of any other covenant or
agreement contained in this Indenture, which default continues for a period of
30 days after the Issuers

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<PAGE>   60

receive written notice specifying the default (and demanding that such default
be remedied) from the Trustee or the Holders of at least 25% of the outstanding
principal amount of the Securities;

         (d) the failure to pay at final stated maturity (giving effect to any
applicable grace periods and any extensions thereof) the principal amount of any
Indebtedness of NATG or any Restricted Subsidiary of NATG (other than
Non-Recourse Debt of a Receivables Entity) or the acceleration of the final
stated maturity of any such Indebtedness (which acceleration is not rescinded,
annulled or otherwise cured within 20 days of receipt by NATG or such Restricted
Subsidiary of notice of any such acceleration) if the aggregate principal amount
of such Indebtedness, together with the principal amount of any other such
Indebtedness in default for failure to pay principal at final maturity or which
has been accelerated (in each case with respect to which the 20-day period
described above has elapsed), aggregates $10.0 million or more at any time;

         (e) one or more judgments in an aggregate amount in excess of $10.0
million shall have been rendered against NATG or any of its Significant
Subsidiaries and such judgments remain undischarged, unpaid or unstayed for a
period of 60 days after such judgment or judgments become final and
non-appealable;

         (f) Parent, an Issuer, or any of their respective Significant
Subsidiaries (i) commences a voluntary case or proceeding under any Bankruptcy
Law with respect to itself, (ii) consents to the entry of a judgment, decree or
order for relief against it in an involuntary case or proceeding under any
Bankruptcy Law, (iii) consents to the appointment of a custodian of it or for
substantially all of its property, (iv) consents to or acquiesces in the
institution of a bankruptcy or an insolvency proceeding against it, (v) makes a
general assignment for the benefit of its creditors or (vi) takes any corporate
action to authorize or effect any of the foregoing;

         (g) a court of competent jurisdiction enters a judgment, decree or
order for relief in respect of Parent, an Issuer or any of their respective
Significant Subsidiaries in an involuntary case or proceeding under any
Bankruptcy Law, which shall (i) approve as properly filed a petition seeking
reorganization, arrangement, adjustment or composition in respect of Parent, an
Issuer or any of their respective Significant Subsidiaries, (ii) appoint a
Custodian of Parent, an Issuer or any of their respective Significant
Subsidiaries or for substantially all of any property of any of them or (iii)
order the winding-up or liquidation of its affairs; and such judgment, decree or
order shall remain unstayed and in effect for a period of 60 consecutive days;
or

         (h) (i) any Guarantee or any provision thereof shall cease to be in
full force or effect (other than in accordance with its express terms), or (ii)
Parent or any other Guarantor or any Person acting by or on behalf of such
Guarantor shall deny or disaffirm such Guarantor's obligations under its
Guarantee, or (iii) Parent or any other Guarantor shall default in the due
performance or observance of any term, covenant or agreement on its part to be
performed or observed, after giving effect to any applicable grace periods,
pursuant to its Guarantee.

         Section 6.2 Acceleration. If an Event of Default (other than an Event
of Default specified in either clause (f) or (g) of Section 6.1 above with
respect to an Issuer) shall occur and be continuing, the Trustee or the Holders
of at least 25% in principal amount of outstanding

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<PAGE>   61

Securities may declare the principal of and accrued interest on all the
Securities to be due and payable by notice in writing to the Issuers (and the
Trustee if given by the Holders) specifying the respective Event of Default and
that it is a "notice of acceleration" (the "Acceleration Notice"), and the same
(i) shall become immediately due and payable or (ii) if there are any amounts
outstanding under the Senior Secured Credit Agreement, shall become immediately
due and payable upon the first to occur of an acceleration under the Senior
Secured Credit Agreement or 5 business days after receipt by the Issuers and the
Representative under the Senior Secured Credit Agreement of such Acceleration
Notice but only if such Event of Default is then continuing. If an Event of
Default specified in either clause (f) or (g) of Section 6.1 above with respect
to an Issuer occurs and is continuing, then all unpaid principal of, and
premium, if any, and accrued and unpaid interest on all of the outstanding
Securities shall ipso facto become and be immediately due and payable without
any declaration or other act on the part of the Trustee or any Holder.

         At any time after a declaration of acceleration with respect to the
Securities as described in the preceding paragraph, the Holders of a majority in
principal amount of the Securities may rescind and cancel such declaration and
its consequences (i) if the rescission would not conflict with any judgment or
decree, (ii) if all existing Events of Default have been cured or waived except
nonpayment of principal or interest that has become due solely because of the
acceleration, (iii) to the extent the payment of such interest is lawful,
interest on overdue installments of interest and overdue principal, which has
become due otherwise than by such declaration of acceleration, has been paid,
(iv) if the Issuers have paid the Trustee its reasonable compensation and
reimbursed the Trustee for its expenses, disbursements and advances and (v) in
the event of the cure or waiver of an Event of Default of the type described in
either clause (f) or (g) of Section 6.1, the Trustee shall have received an
Officers' Certificate from each Issuer and an Opinion of Counsel that such Event
of Default has been cured or waived. No such rescission shall affect any
subsequent Default or impair any right consequent thereto.

         Section 6.3 Other Remedies. If an Event of Default occurs and is
continuing, the Trustee may pursue any available remedy by proceeding at law or
in equity to collect the payment of principal of or interest on the Securities
or to enforce the performance of any provision of the Securities or this
Indenture.

         The Trustee may maintain a proceeding even if it does not possess any
of the Securities or does not produce any of them in the proceeding. A delay or
omission by the Trustee or any Securityholder in exercising any right or remedy
accruing upon an Event of Default shall not impair the right or remedy or
constitute a waiver of or acquiescence in the Event of Default. No remedy is
exclusive of any other remedy. All available remedies are cumulative to the
extent permitted by law.

         Section 6.4 Waiver of Past Defaults. Subject to Sections 2.9, 6.7 and
9.2, the Holders of not less than a majority in principal amount of the
outstanding Securities by notice to the Trustee may waive an existing Default or
Event of Default and its consequences, except a Default in the payment of
principal of or interest on any Security as specified in clauses (a) and (b) of
Section 6.1. Each Issuer shall deliver to the Trustee an Officers' Certificate
stating that the requisite

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<PAGE>   62

percentage of Holders have consented to such waiver and attaching copies of such
consents. When a Default or Event of Default is waived, it is cured and ceases.

         Section 6.5 Control by Majority. The Holders of not less than a
majority in principal amount of the outstanding Securities may direct the time,
method and place of conducting any proceeding for any remedy available to the
Trustee or exercising any trust or power conferred on it. Subject to Section
7.1, however, the Trustee may refuse to follow any direction that conflicts with
any law or this Indenture, that the Trustee determines may be unduly prejudicial
to the rights of another Securityholder, or that may involve the Trustee in
personal liability; provided, that the Trustee may take any other action deemed
proper by the Trustee which is not inconsistent with such direction.

         In the event the Trustee takes any action or follows any direction
pursuant to this Indenture, the Trustee shall be entitled to indemnification
satisfactory to it in its sole discretion against any loss or expense caused by
taking such action or following such direction.

         Section 6.6 Limitation on Suits. A Securityholder may not pursue any
remedy with respect to this Indenture or the Securities unless:

         (1)  the Holder gives to the Trustee written notice of a continuing
Event of Default;

         (2) the Holder or Holders of at least 25% in principal amount of the
outstanding Securities make a written request to the Trustee to pursue the
remedy;

         (3) such Holder or Holders offer and, if requested, provide to the
Trustee indemnity satisfactory to the Trustee against any loss, liability or
expense;

         (4) the Trustee does not comply with the request within 45 days after
receipt of the request and the offer and, if requested, the provision of
indemnity; and

         (5) during such 45-day period the Holder or Holders of a majority in
principal amount of the outstanding Securities do not give the Trustee a
direction which, in the opinion of the Trustee, is inconsistent with the
request.

         A Securityholder may not use this Indenture to prejudice the rights of
another Securityholder or to obtain a preference or priority over such other
Securityholder.

         Section 6.7 Rights of Holders To Receive Payment. Notwithstanding any
other provision of this Indenture, the right of any Holder to receive payment of
principal of and interest on a Security, on or after the respective due dates
expressed in such Security, or to bring suit for the enforcement of any such
payment on or after such respective dates, shall not be impaired or affected
without the consent of the Holder.

         Section 6.8 Collection Suit by Trustee. If an Event of Default in
payment of principal or interest specified in clause (a) or (b) of Section 6.1
occurs and is continuing, the Trustee may recover judgment in its own name and
as trustee of an express trust against the Issuers or any

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<PAGE>   63

other obligor on the Securities or the Guarantees for the whole amount of
principal and accrued interest and fees remaining unpaid, together with interest
on overdue principal and, to the extent that payment of such interest is lawful,
interest on overdue installments of interest, in each case at the rate per annum
borne by the Securities and such further amount as shall be sufficient to cover
the costs and expenses of collection, including the reasonable compensation,
expenses, disbursements and advances of the Trustee, its agents and counsel.

         Section 6.9 Trustee May File Proofs of Claim. The Trustee may file such
proofs of claim and other papers or documents as may be necessary or advisable
in order to have the claims of the Trustee (including any claim for the
reasonable compensation, expenses, disbursements and advances of the Trustee,
its agents and counsel) and the Securityholders allowed in any judicial
proceedings relating to any Issuer or Guarantor, their respective creditors or
property, and shall be entitled and empowered to participate as a member, voting
or otherwise, of any official committee of creditors appointed in such matter
and to collect and receive any monies or other property payable or deliverable
on any such claims and to distribute the same, and any Custodian in any such
judicial proceedings is hereby authorized by each Securityholder to make such
payments to the Trustee and, in the event that the Trustee shall consent to the
making of such payments directly to the Securityholders, to pay to the Trustee
any amount due to it for the reasonable compensation, expenses, disbursements
and advances of the Trustee, its agent and counsel, and any other amounts due
the Trustee under Section 7.7. Nothing herein contained shall be deemed to
authorize the Trustee to authorize or consent to or accept or adopt on behalf of
any Securityholder any plan of reorganization, arrangement, adjustment or
composition affecting the Securities or the rights of any Holder thereof, or to
authorize the Trustee to vote in respect of the claim of any Securityholder in
any such proceeding.

         Section 6.10 Priorities. If the Trustee collects any money or property
pursuant to this Article Six, it shall pay out the money or property in the
following order:

         First:  to the Trustee for amounts due under Section 7.7;

         Second:  to Holders for interest  accrued on the Securities,  ratably,
without preference or priority of ny kind, according to the amounts due and
payable on the Securities for interest;

         Third: to Holders for principal amounts due and unpaid on the
Securities, ratably, without preference or priority of any kind, according to
the amounts due and payable on the Securities for principal; and

         Fourth: to the Issuers or, if applicable, the Guarantors, as their
respective interests may appear.

         The Trustee, upon prior notice to the Issuers, may fix a record date
and payment date for any payment to Securityholders pursuant to this Section
6.10.

         Section 6.11 Undertaking for Costs. In any suit for the enforcement of
any right or remedy under this Indenture or in any suit against the Trustee for
any action taken or omitted by it as Trustee, a court in its discretion may
require the filing by any party litigant in the suit of an

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<PAGE>   64

undertaking to pay the costs of the suit, and the court in its discretion may
assess reasonable costs, including reasonable attorneys' fees, against any party
litigant in the suit, having due regard to the merits and good faith of the
claims or defenses made by the party litigant. This Section 6.11 does not apply
to a suit by the Trustee, a suit by a Holder pursuant to Section 6.7, or a suit
by a Holder or Holders of more than 10% in principal amount of the outstanding
Securities.

                                  ARTICLE SEVEN

                                     TRUSTEE

         Section 7.1 Duties of Trustee. (a) If an Event of Default has occurred
and is continuing, the Trustee shall exercise such of the rights and powers
vested in it by this Indenture and use the same degree of care and skill in
their exercise as a prudent person would exercise or use under the circumstances
in the conduct of his or her own affairs.

         (b)  Except during the continuance of an Event of Default:

                  (1) The Trustee need perform only those duties as are
         specifically set forth herein or in the TIA and no duties, covenants,
         responsibilities or obligations shall be implied in this Indenture
         against the Trustee.

                  (2) In the absence of bad faith on its part, the Trustee may
         conclusively rely, as to the truth of the statements and the
         correctness of the opinions expressed therein, upon certificates
         (including Officers' Certificates) or opinions (including Opinions of
         Counsel) furnished to the Trustee and conforming to the requirements of
         this Indenture. However, the Trustee shall examine the certificates and
         opinions to determine whether or not they conform to the requirements
         of this Indenture, but shall not be obligated to verify the contents
         thereof.

         (c) Notwithstanding anything to the contrary herein, the Trustee may
not be relieved from liability for its own negligent action, its own negligent
failure to act, or its own willful misconduct, except that:

                  (1) This paragraph (c) does not limit the effect of paragraph
         (b) of this Section 7.1.

                  (2) The Trustee shall not be liable for any error of judgment
         made in good faith by a Responsible Officer, unless it is proved that
         the Trustee was negligent in ascertaining the pertinent facts.

                  (3) The Trustee shall not be liable with respect to any action
         it takes or omits to take in good faith in accordance with a direction
         received by it pursuant to Section 6.5.

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<PAGE>   65

         (d) No provision of this Indenture shall require the Trustee to expend
or risk its own funds or otherwise incur any financial liability in the
performance of any of its duties hereunder or to take or omit to take any action
under this Indenture or take any action at the request or direction of Holders
if it shall have reasonable grounds for believing that repayment of such funds
is not assured to it.

         (e) Every provision of this Indenture that in any way relates to the
Trustee is subject to this Section 7.1.

         (f) The Trustee shall not be liable for interest on any money received
by it except as the Trustee may agree in writing with the Issuers. Money held in
trust by the Trustee need not be segregated from other funds except to the
extent required by law.

         (g) In the absence of bad faith, negligence or willful misconduct on
the part of the Trustee, the Trustee shall not be responsible for the
application of any money by any Paying Agent other than the Trustee.

         Section 7.2  Rights of Trustee.  Subject to Section 7.1:

         (a) The Trustee may rely on any document believed by it to be genuine
and to have been signed or presented by the proper Person. The Trustee need not
investigate any fact or matter stated in the document.

         (b) Before the Trustee acts or refrains from acting, it may require an
Officers' Certificate and an Opinion of Counsel, which shall to the extent
relevant, conform to the provisions of Section 13.5. The Trustee shall not be
liable for any action it takes or omits to take in good faith in reliance on
such certificate or opinion.

         (c) The Trustee may act through its attorneys and agents and shall not
be responsible for the misconduct or negligence of any agent (other than an
agent who is an employee of the Trustee) appointed with due care.

         (d) The Trustee shall not be liable for any action it takes or omits to
take in good faith which it reasonably believes to be authorized or within its
rights or powers.

         (e) The Trustee may consult with counsel and the advice or opinion of
such counsel as to matters of law shall be full and complete authorization and
protection from liability in respect of any action taken, omitted or suffered by
it hereunder in good faith and in accordance with the advice or opinion of such
counsel.

         (f) The Trustee shall be under no obligation to exercise any of the
rights or powers vested in it by this Indenture at the request, order or
direction of any of the Holders pursuant to the provisions of this Indenture,
unless such Holders shall have offered to the Trustee reasonable security or
indemnity against the costs, expenses and liabilities which may be incurred
therein or thereby.

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<PAGE>   66

         (g) The Trustee shall not be bound to make any investigation into the
facts or matters stated in any resolution, certificate (including any Officers'
Certificate), statement, instrument, opinion (including any Opinion of Counsel),
notice, request, direction, consent, order, bond, debenture, or other paper or
document, but the Trustee, in its discretion, may make such further inquiry or
investigation into such facts or matters as it may see fit and, if the Trustee
shall determine to make such further inquiry or investigation, it shall be
entitled, upon reasonable notice to the Issuers, to examine the books, records,
and premises of the Issuers, personally or by agent or attorney.

         (h) The Trustee shall not be required to give any bond or surety in
respect of the performance of its powers and duties hereunder.

         (i) The permissive rights of the Trustee to do things enumerated in
this Indenture shall not be construed as duties.

         Section 7.3 Individual Rights of Trustee. The Trustee in its individual
or any other capacity may become the owner or pledgee of Securities and may
otherwise deal with the Issuers, their respective Subsidiaries, and their
respective Affiliates with the same rights it would have if it were not Trustee.
Any Agent may do the same with like rights. However, the Trustee must comply
with Sections 7.10 and 7.11.

         Section 7.4 Trustee's Disclaimer. The Trustee shall not be responsible
for and makes no representation as to the validity or adequacy of this Indenture
or the Securities, it shall not be accountable for the Issuers' use of the
proceeds from the issuance of the Securities, and it shall not be responsible
for any statement of the Issuers or the Guarantors in this Indenture or any
document issued in connection with the sale of Securities or any statement in
the Securities other than the Trustee's certificate of authentication. The
Trustee makes no representations with respect to the effectiveness or adequacy
of this Indenture.

         Section 7.5 Notice of Default. If a Default or an Event of Default
occurs and is continuing and the Trustee receives actual notice of such Default
or Event of Default, the Trustee shall mail to each Securityholder notice of the
uncured Default or Event of Default within 60 days after such Default or Event
of Default occurs. Except in the case of a Default or an Event of Default in
payment of principal of, or interest on, any Security, including an accelerated
payment and the failure to make payment on the Change of Control Payment Date
pursuant to a Change of Control Offer or the Net Proceeds Offer Payment Date
pursuant to a Net Proceeds Offer, the Trustee may withhold the notice if and so
long as the Board of Directors, the executive committee, or a trust committee of
directors and/or Responsible Officers, of the Trustee in good faith determines
that withholding the notice is in the interest of the Securityholders.

         Section 7.6 Reports by Trustee to Holders. Within 60 days after each
May 15, beginning with the first May 15 following the date of this Indenture,
the Trustee shall, to the extent that any of the events described in TIA ss.
313(a) occurred within the previous twelve months, but not otherwise, mail to
each Securityholder a brief report dated as of such date that complies with TIA
ss. 313(a). The Trustee also shall comply with TIA ss.ss. 313(b), 313(c) and
313(d).

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<PAGE>   67

         A copy of each report at the time of its mailing to Securityholders
shall be mailed to the Issuers and filed with the Commission and each securities
exchange, if any, on which the Securities are then listed.

         The Issuers shall notify the Trustee if the Securities become listed on
any securities exchange or of any delisting thereof and the Trustee shall comply
with TIA ss. 313(d).

         Section 7.7 Compensation and Indemnity. The Issuers shall pay to the
Trustee from time to time reasonable compensation for its services hereunder.
The Trustee's compensation shall not be limited by any law on compensation of a
trustee of an express trust. The Issuers shall reimburse the Trustee upon
request for all reasonable disbursements, expenses and advances (including
reasonable fees and expenses of counsel) incurred or made by it in addition to
the compensation for its services, except any such disbursements, expenses and
advances as may be attributable to the Trustee's negligence, bad faith or
willful misconduct. Such expenses shall include the reasonable fees and expenses
of the Trustee's agents and counsel.

         The Issuers shall indemnify the Trustee and its agents, employees,
officers, stockholders and directors for, and hold them harmless against, any
claim (whether asserted by the Issuers or any other Person), loss, liability or
expense incurred by them except for such actions to the extent caused by any
negligence, bad faith or willful misconduct on their part, arising out of or in
connection with the acceptance or administration of this trust including the
costs and expenses of enforcing this Indenture against the Issuers (including
this Section 7.7), including the reasonable costs and expenses of defending
themselves against or investigating any claim or liability in connection with
the exercise or performance of any of the Trustee's rights, powers or duties
hereunder. The Trustee shall notify the Issuers promptly of any claim asserted
against the Trustee or any of its agents, employees, officers, stockholders and
directors for which it may seek indemnity. The Issuers may, subject to the
approval of the Trustee, defend the claim and the Trustee shall cooperate in the
defense. The Trustee and its agents, employees, officers, stockholders and
directors subject to the claim may have separate counsel and the Issuers shall
pay the reasonable fees and expenses of such counsel; provided, that the Issuers
will not be required to pay such fees and expenses if, subject to the approval
of the Trustee, it assumes the Trustee's defense and there is no conflict of
interest between the Issuers and the Trustee and its agents, employees,
officers, stockholders and directors subject to the claim in connection with
such defense as reasonably determined by the Trustee. The Issuers need not pay
for any settlement made without their written consent, which consent will not be
unreasonably withheld or delayed. The Issuers need not reimburse any expense or
indemnify against any loss or liability to the extent incurred by the Trustee
through its negligence, bad faith or willful misconduct.

         To secure the Issuers' payment obligations in this Section 7.7, the
Trustee shall have a senior claim prior to the Securities against all money or
property held or collected by the Trustee, in its capacity as Trustee, except
assets or money held in trust to pay principal of or interest on particular
Securities.

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<PAGE>   68

         When the Trustee incurs expenses or renders services after an Event of
Default specified in clause (f) or (g) of Section 6.1 occurs, such expenses and
the compensation for such services shall be paid to the extent allowed under any
Bankruptcy Law.

         Notwithstanding any other provision in this Indenture, the foregoing
provisions of this Section 7.7 shall survive the satisfaction and discharge of
this Indenture or the appointment of a successor Trustee.

         Section 7.8 Replacement of Trustee. The Trustee may resign at any time
by so notifying the Issuers in writing. The Holders of a majority in principal
amount of the outstanding Securities may remove the Trustee by so notifying the
Issuers and the Trustee and may appoint a successor Trustee. The Issuers may
remove the Trustee if:

         (1)  the Trustee fails to comply with Section 7.10;

         (2)  the Trustee is adjudged a bankrupt or an insolvent;

         (3) a receiver or other public officer takes charge of the Trustee or
             its property; or

         (4) the Trustee becomes incapable of acting as trustee hereunder.

         If the Trustee resigns or is removed or if a vacancy exists in the
office of Trustee for any reason, the Issuers shall notify each Holder of such
event and shall promptly appoint a successor Trustee. Within one year after the
successor Trustee takes office, the Holders of a majority in principal amount of
the Securities may appoint a successor Trustee to replace the successor Trustee
appointed by the Issuers.

         A successor Trustee shall deliver a written acceptance of its
appointment to the retiring Trustee and to the Issuers. Immediately after that,
the retiring Trustee shall transfer, after payment of all sums then owing to the
Trustee pursuant to Section 7.7, all property held by it as Trustee to the
successor Trustee, subject to the Lien provided in Section 7.7, the resignation
or removal of the retiring Trustee shall become effective, and the successor
Trustee shall have all the rights, powers and duties of the Trustee under this
Indenture. A successor Trustee shall mail notice of its succession to each
Securityholder.

         If a successor Trustee does not take office within 60 days after the
retiring Trustee resigns or is removed, the retiring Trustee, the Issuers or the
Holders of at least 10% in principal amount of the outstanding Securities may
petition any court of competent jurisdiction for the appointment of a successor
Trustee.

         If the Trustee fails to comply with Section 7.10, any Securityholder
may petition any court of competent jurisdiction for the removal of the Trustee
and the appointment of a successor Trustee.

         Notwithstanding replacement of the Trustee pursuant to this Section
7.8, the Issuers' obligations under Section 7.7 shall continue for the benefit
of the retiring Trustee.

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<PAGE>   69

         Section 7.9 Successor Trustee by Merger, Etc. If the Trustee
consolidates with, merges or converts into, or transfers all or substantially
all of its corporate trust business to, another corporation, the resulting,
surviving or transferee corporation without any further act shall, if such
resulting, surviving or transferee corporation is otherwise eligible hereunder,
be the successor Trustee, provided that such corporation shall be otherwise
qualified and eligible under this Article Seven.

         Section 7.10 Eligibility; Disqualification. This Indenture shall always
have a Trustee who satisfies the requirement of TIA ss.ss. 310(a)(1), 310(a)(2)
and 310(a)(5). The Trustee shall have a combined capital and surplus of at least
$50.0 million as set forth in its most recent published annual report of
condition. In addition, if the Trustee is a corporation included in a bank
holding company system, the Trustee, independently of the bank holding company,
shall meet the capital requirements of TIA ss. 310(a)(2). The Trustee shall
comply with TIA ss. 310(b); provided, that there shall be excluded from the
operation of TIA ss. 310(b)(1) any indenture or indentures under which other
securities, or certificates of interest or participation in other securities, of
the Issuers are outstanding, if the requirements for such exclusion set forth in
TIA ss. 310(b)(1) are met. The provisions of TIA ss. 310 shall apply to the
Issuers and any other obligor of the Securities.

         Section 7.11 Preferential Collection of Claims Against Company. The
Trustee, in its capacity as Trustee hereunder shall comply with TIA ss. 311(a),
excluding any creditor relationship listed in TIA ss. 311(b). A Trustee who has
resigned or been removed shall be subject to TIA ss. 311(a) to the extent
indicated.

                                  ARTICLE EIGHT

                       DISCHARGE OF INDENTURE; DEFEASANCE

         Section 8.1 Termination of the Issuers' Obligations. The Issuers may
terminate their obligations in respect of the Securities and this Indenture,
except those obligations referred to in the penultimate paragraph of this
Section 8.1, if all Securities previously authenticated and delivered (other
than destroyed, lost or stolen Securities which have been replaced or paid or
Securities for whose payment U.S. Legal Tender has theretofore been deposited
with the Trustee or the Paying Agent in trust or segregated and held in trust by
the Issuers and thereafter repaid to the Issuers, as provided in Section 8.5)
have been delivered to the Trustee for cancellation and the Issuers have paid
all sums payable by it hereunder, or if:

         (a) either (i) pursuant to Article Three, the Issuers shall have given
notice to the Trustee, and mailed a notice of redemption to each Holder, of the
redemption of all of the Securities in accordance with the provisions hereof or
(ii) all Securities have otherwise become due and payable hereunder;

         (b) the Issuers shall have irrevocably deposited or caused to be
deposited with the Trustee or a trustee satisfactory to the Trustee, under the
terms of an irrevocable trust agreement in form and substance satisfactory to
the Trustee, as trust funds in trust solely for the benefit of the Holders of
that purpose, U.S. Legal Tender in such amount as is sufficient without

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<PAGE>   70

consideration of reinvestment of such interest, to pay principal of, premium, if
any, and interest on the outstanding Securities to maturity or redemption;
provided, that the Trustee shall have been irrevocably instructed to apply such
U.S. Legal Tender to the payment of said principal, premium, if any, and
interest with respect to the Securities and provided, further, that from and
after the time of deposit, the money deposited shall not be subject to the
rights of holders of Senior Debt or Guarantor Senior Debt pursuant to the
provisions of Article Ten or Twelve, as the case may be;

         (c) no Default or Event of Default with respect to this Indenture or
the Securities shall have occurred and be continuing on the date of such deposit
or shall occur as a result of such deposit and such deposit will not result in a
breach or violation of, or constitute a default under, this Indenture, the
Senior Secured Credit Agreement, any other material agreement or instrument to
which Parent or any of its Subsidiaries is a party or by which it is bound;

         (d) the Issuers shall have paid all other sums payable by them
hereunder; and

         (e) each Issuer shall have delivered to the Trustee an Officers'
Certificate and an Opinion of Counsel, each stating that all conditions
precedent providing for or relating to the termination of such Issuers'
obligations in respect of the Securities and this Indenture have been complied
with. Each such Opinion of Counsel shall also state that such satisfaction and
discharge does not result in a default under the Senior Credit Agreement or any
other material agreement or instrument then known to such counsel that binds or
affects such Issuer.

         Subject to the next sentence and notwithstanding the foregoing
paragraph, the Issuers' obligations in Sections 2.5, 2.6, 2.7, 2.8, 4.1, 4.2,
7.7, 8.5 and 8.6 shall survive until the Securities are no longer outstanding
pursuant to the last paragraph of Section 2.8. After the Securities are no
longer outstanding, the Issuers' obligations in Sections 7.7, 8.5 and 8.6 shall
survive.

         After such delivery or irrevocable deposit, the Trustee upon request
shall acknowledge in writing the discharge of the Issuers' obligations under the
Securities and this Indenture except for those surviving obligations specified
above.

         Section 8.2 Legal Defeasance and Covenant Defeasance. (a) The Issuers
may, at their option by Board Resolution of the Board of Directors of each
Issuer, at any time, elect to have either paragraph (b) or (c) below be applied
to all outstanding Securities upon compliance with the conditions set forth in
Section 8.3.

         (b) Upon the Issuers' exercise under paragraph (a) hereof of the option
applicable to this paragraph (b), the Issuers shall, subject to the satisfaction
of the conditions set forth in Section 8.3, be deemed to have been discharged
from their obligations with respect to all outstanding Securities on the date
the conditions set forth below are satisfied (hereinafter, "Legal Defeasance").
For this purpose, Legal Defeasance means that the Issuers shall be deemed to
have paid and discharged the entire Indebtedness represented by the outstanding
Securities, which shall thereafter be deemed to be "outstanding" only for the
purposes of Section 8.4 and the other Sections of this Indenture referred to in
clauses (i) and (ii) below, and to have satisfied all

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<PAGE>   71

its other obligations in respect of such Securities and this Indenture (and the
Trustee, on demand of and at the expense of the Issuers, shall execute proper
instruments prepared by the Issuers acknowledging the same), and Holders of the
Securities and any amounts deposited under Section 8.3 shall cease to be subject
to any obligations to, or the rights of, any holder of Senior Debt under Article
Ten or otherwise, except for the following provisions, which shall survive until
otherwise terminated or discharged hereunder: (i) the rights of Holders of
outstanding Securities to receive solely from the trust fund described in
Section 8.4, and as more fully set forth in such Section, payments in respect of
the principal of premium, if any, and interest on such Securities when such
payments are due, (ii) the Issuers' obligations with respect to such Securities
under Article Two and Section 4.2 hereof, (iii) the rights, powers, trusts,
duties and immunities of the Trustee hereunder and the Issuers' obligations in
connection therewith and (iv) this Article Eight. Subject to compliance with
this Article Eight, the Issuers may exercise their option under this paragraph
(b) notwithstanding the prior exercise of its option under paragraph (c) hereof.

         (c) Upon the Issuers' exercise under paragraph (a) hereof of the option
applicable to this paragraph (c), the Issuers shall, subject to the satisfaction
of the conditions set forth in Section 8.3 hereof, be released from their
obligations under the covenants contained in Sections 4.3, 4.4 and Sections 4.12
through 4.22 and Article Five hereof with respect to the outstanding Securities
on and after the date the conditions set forth below are satisfied (hereinafter,
"Covenant Defeasance"), and the Securities shall thereafter be deemed not
"outstanding" for the purposes of any direction, waiver, consent or declaration
or act of Holders (and the consequences of any thereof) in connection with such
covenants, but shall continue to be deemed "outstanding" for all other purposes
hereunder (it being understood that such Securities shall not be deemed
outstanding for accounting purposes) and Holders of the Securities and any
amounts deposited under Section 8.3 hereof shall cease to be subject to any
obligations to, or the rights of, any holder of Senior Debt under Article Ten or
otherwise. For this purpose, such Covenant Defeasance means that, with respect
to the outstanding Securities, the Issuers may omit to comply with and shall
have no liability in respect of any term, condition or limitation set forth in
any such covenant, whether directly or indirectly, by reason of any reference
elsewhere herein to any such covenant or by reason of any reference in any such
covenant to any other provision herein or in any other document and such
omission to comply shall not constitute a Default or an Event of Default under
Section 6.1(c) hereof, but, except as specified above, the remainder of this
Indenture and such Securities shall be unaffected thereby. In addition, upon the
Issuers' exercise under paragraph (a) hereof of the option applicable to this
paragraph (c), subject to the satisfaction of the conditions set forth in
Section 8.3 hereof, Sections 6.1(c), 6.1(d) and 6.1(e) shall not constitute
Events of Default.

         Section 8.3 Conditions to Legal Defeasance or Covenant Defeasance. The
following shall be the conditions to the application of either Section 8.2(b) or
8.2(c) hereof to the outstanding Securities:

         In order to exercise either Legal Defeasance or Covenant Defeasance:

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<PAGE>   72

         (a) the Issuers must irrevocably deposit with the Trustee, in trust,
for the benefit of the Holders, U.S. Legal Tender or U.S. Government Obligations
or a combination thereof which through the scheduled payment of principal and
interest in respect thereof in accordance with their terms, will provide, not
later than one day before the due date of any payment on the Securities, U.S.
Legal Tender in such amounts as will be sufficient, in the opinion of a
nationally recognized firm of independent public accountants, to pay the
principal of, premium, if any, and interest on the Securities on the stated date
for payment thereof or on the applicable Redemption Date, as the case may be;

         (b) in the case of a Legal Defeasance, each Issuer shall have delivered
to the Trustee an Opinion of Counsel in the United States reasonably acceptable
to the Trustee confirming that (A) the Issuers have received from, or there has
been published by, the Internal Revenue Service a ruling or (B) since the date
of this Indenture, there has been a change in the applicable federal income tax
law, in either case to the effect that, and based thereon such Opinion of
Counsel shall confirm that, the Holders will not recognize income, gain or loss
for federal income tax purposes as a result of such Legal Defeasance and will be
subject to federal income tax on the same amounts, in the same manner and at the
same times as would have been the case if such Legal Defeasance had not
occurred;

         (c) in the case of a Covenant Defeasance, each Issuer shall have
delivered to the Trustee an Opinion of Counsel in the United States reasonably
acceptable to the Trustee confirming that the Holders of the Securities will not
recognize income, gain or loss for federal income tax purposes as a result of
such Covenant Defeasance and will be subject to federal income tax on the same
amounts, in the same manner and at the same times as would have been the case if
such Covenant Defeasance had not occurred;

         (d) no Default or Event of Default shall have occurred and be
continuing on the date of such deposit (other than a Default or Event of Default
resulting from the incurrence of Indebtedness all or a portion of the proceeds
of which will be used to defease the Securities pursuant to this Article Eight
concurrently with such incurrence and the grant of any Lien securing such
incurrence) or insofar as Sections 6.1(f) and 6.1(g) hereof are concerned, at
any time in the period ending on the 91st day after the date of such deposit;

         (e) such Legal Defeasance or Covenant Defeasance shall not result in a
breach or violation of, or constitute a default under this Indenture (other than
a Default or Event of Default resulting from the incurrence of Indebtedness all
or a portion of the proceeds of which will be used to defease the Securities
pursuant to this Article Eight concurrently with such incurrence and the grant
of any Lien securing such incurrence), the Senior Secured Credit Agreement or
any other material agreement or instrument to which Parent or any of its
Restricted Subsidiaries is a party or by which Parent or any of its Restricted
Subsidiaries is bound;

         (f) each Issuer shall have delivered to the Trustee an Officers'
Certificate stating that the deposit was not made by the Issuers with the intent
of preferring the Holders over any other creditors of the Issuers or with the
intent of defeating, hindering, delaying or defrauding any other creditors of
the Issuers or others;

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<PAGE>   73

         (g) each Issuer shall have delivered to the Trustee an Officers'
Certificate and an Opinion of Counsel, each stating that all conditions
precedent provided for or relating to the Legal Defeasance or the Covenant
Defeasance have been complied with;

         (h) each Issuer shall have delivered to the Trustee an Opinion of
Counsel to the effect that (i) the trust funds will not be subject to any rights
of any holders of Senior Debt or Guarantor Senior Debt, including, without
limitation, those arising under this Indenture, and (ii) assuming no intervening
bankruptcy or insolvency of an Issuer between the date of deposit and the 91st
day following the deposit and that no Holder is an insider of an Issuer, after
the 91st day following the deposit, the trust funds will not be subject to the
effect of any applicable Bankruptcy Law; and

         (i) if at the time, Securities are listed on a national securities
exchange, each Issuer shall have delivered to the Trustee and Opinion of Counsel
to the effect that the Securities will not be delisted as a result of such
deposit, defeasance and discharge.

         Notwithstanding the foregoing, the Opinion of Counsel required by
clause (b) above of this Section 8.3 with respect to a Legal Defeasance need not
be delivered if all Securities not theretofore delivered to the Trustee for
cancellation (i) have become due and payable or (ii) will become due and payable
on the Maturity Date within one year under arrangements satisfactory to the
Trustee for the giving of notice of redemption by the Trustee in the name, and
at the expense, of the Issuers.

         Section 8.4 Application of Trust Money. The Trustee or Paying Agent
shall hold in trust U.S. Legal Tender or U.S. Government Obligations deposited
with it pursuant to this Article Eight, and shall apply the deposited U.S. Legal
Tender and the money from U.S. Government Obligations in accordance with this
Indenture to the payment of principal of and interest on the Securities. The
Trustee shall be under no obligation to invest said U.S. Legal Tender or U.S.
Government Obligations except as it may agree with the Issuers.

         The Issuers shall pay and indemnify the Trustee against any tax, fee or
other charge imposed on or assessed against the U.S. Legal Tender or U.S.
Government Obligations deposited pursuant to Section 8.3 hereof or the principal
and interest received in respect thereof other than any such tax, fee or other
charge which by law is for the account of the Holders of the outstanding
Securities.

         Anything in this Article Eight to the contrary notwithstanding, the
Trustee shall deliver or pay to the Issuers from time to time upon the Issuers'
request any U.S. Legal Tender or U.S. Government Obligations held by it as
provided in Section 8.3 hereof the amount of which, in the opinion of a
nationally recognized firm of independent public accountants expressed in a
written certification thereof delivered to the Trustee, is in excess of the
amount thereof that would then be required to be deposited to effect an
equivalent Legal Defeasance or Covenant Defeasance.

         Section 8.5 Repayment to the Issuers. Subject to this Article Eight,
the Trustee and the Paying Agent shall promptly pay to the Issuers upon request
any excess U.S. Legal Tender or U.S. Government Obligations held by them at any
time and thereupon shall be relieved from all

                                      -69-
<PAGE>   74

liability with respect to such money. The Trustee and the Paying Agent shall pay
to the Issuers upon request any money held by them for the payment of principal
or interest that remains unclaimed for two years; provided, that the Trustee or
such Paying Agent, before being required to make any payment, may at the expense
of the Issuers cause to be published once in a newspaper of general circulation
in The City of New York and mail to each Holder entitled to such money notice
that such money remains unclaimed and that after a date specified therein which
shall be at least 30 days from the date of such publication and mailing any
unclaimed balance of such money then remaining will be repaid to the Issuers.
After payment to the Issuers, Holders entitled to such money must look to the
Issuers for payment as general creditors unless an applicable law designates
another Person.

         Section 8.6 Reinstatement. If the Trustee or Paying Agent is unable to
apply any U.S. Legal Tender or U.S. Government Obligations in accordance with
this Article Eight by reason of any legal proceeding or by reason of any order
or judgment of any court or governmental authority enjoining, restraining or
otherwise prohibiting such application, the Issuers' obligations under this
Indenture and the Securities shall be revived and reinstated as though no
deposit had occurred pursuant to this Article Eight until such time as the
Trustee or Paying Agent is permitted to apply all such U.S. Legal Tender or U.S.
Government Obligations in accordance with this Article Eight; provided, that if
the Issuers have made any payment of interest on or principal of any Securities
because of the reinstatement of its obligations, the Issuers shall be subrogated
to the rights of the Holders of such Securities to receive such payment from the
U.S. Legal Tender or U.S. Government Obligations held by the Trustee or Paying
Agent.

                                  ARTICLE NINE

                       AMENDMENTS, SUPPLEMENTS AND WAIVERS

         Section 9.1 Without Consent of Holders. Subject to Section 9.3, the
Issuers, the Guarantors and the Trustee, together, may amend or supplement this
Indenture, the Securities or the Guarantees without notice to or consent of any
Securityholder:

         (1)  to cure any ambiguity, defect or inconsistency;

         (2) to evidence the succession in accordance with Article Five hereof
of another Person to an Issuer and the assumption by any such successor of the
covenants of such Issuer herein and in the Securities;

         (3) to provide for uncertificated Securities in addition to or in place
of certificated Securities;

         (4) to make any other change that does not adversely affect the rights
of any Securityholders hereunder in any material respect;

         (5) to comply with any requirements of the Commission in connection
with the qualification of this Indenture under the TIA; or

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<PAGE>   75

         (6) to add or release any Guarantor pursuant to the terms of this
Indenture;

provided that each Issuer has delivered to the Trustee an Opinion of Counsel and
an Officers' Certificate, each stating that such amendment or supplement
complies with the provisions of this Section 9.1.

         Section 9.2 With Consent of Holders. Subject to Sections 6.7 and 9.3,
the Issuers, the Guarantors and the Trustee, together, with the written consent
of the Holder or Holders of at least a majority in aggregate principal amount of
the outstanding Securities, may amend or supplement this Indenture, the
Securities or the Guarantees, without notice to any other Securityholders.
Subject to Sections 6.7 and 9.3, the Holder or Holders of a majority in
aggregate principal amount of the outstanding Securities may waive compliance by
the Issuers or the Guarantors with any provision of this Indenture, the
Securities or the Guarantees without notice to any other Securityholder. Without
the consent of each Securityholder affected, however, no amendment, supplement
or waiver, including a waiver pursuant to Section 6.4, may:

         (1) reduce the amount of Securities the Holders of which must consent
to an amendment, supplement or waiver;

         (2) reduce the rate of or change or have the effect of changing the
time for payment of interest, including default interest, on any Securities;

         (3) reduce the principal of or change or have the effect of changing
the fixed maturity of any Securities, or change the date on which any Securities
may be subject to redemption or repurchase, or reduce the redemption or purchase
price therefor;

         (4) make any Securities payable in money other than that stated in the
Securities;

         (5) make any change in provisions of this Indenture protecting the
right of each Holder to receive payment of principal of and interest on such
Security on or after the due date thereof or to bring suit to enforce such
payment;

         (6) modify or change any provision of this Indenture or the related
definitions affecting the subordination or ranking of the Securities or any
Guarantee in a manner which adversely affects the Holders; or

         (7) release (i) Parent or (ii) any Guarantor that is a Significant
Subsidiary of Parent or an Issuer from any of its obligations under its
Guarantee or this Indenture otherwise than in accordance with the terms of this
Indenture.

         It shall not be necessary for the consent of the Holders under this
Section 9.2 to approve the particular form of any proposed amendment, supplement
or waiver, but it shall be sufficient if such consent approves the substance
thereof.

         After an amendment, supplement or waiver under this Section 9.2 becomes
effective, the Issuers shall mail to the Holders affected thereby a notice
briefly describing the amendment,

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<PAGE>   76

supplement or waiver. Any failure of the Issuers to mail such notice, or any
defect therein, shall not, however, in any way impair or affect the validity of
any such supplemental indenture.

         Section 9.3 Effect on Senior Debt. No amendment of, or supplement or
waiver to, this Indenture shall adversely affect the rights of any holder of
Senior Debt or Guarantor Senior Debt under Article Ten or Article Twelve, as the
case may be, of this Indenture, without the consent of such holder.

         Section 9.4 Compliance with TIA. From the date on which this Indenture
is qualified under the TIA, every amendment, waiver or supplement of this
Indenture, the Securities or the Guarantees shall comply with the TIA as then in
effect.

         Section 9.5 Revocation and Effect of Consents. Until an amendment,
waiver or supplement becomes effective, a consent to it by a Holder is a
continuing consent by the Holder and every subsequent Holder of a Security or
portion of a Security that evidences the same debt as the consenting Holder's
Security, even if notation of the consent is not made on any Security. However,
any such Holder or subsequent Holder may revoke the consent as to his Security
or portion of his Security by notice to the Trustee or the Issuers received
before the date on which the Trustee receives Officers' Certificates from the
Issuers certifying that the Holders of the requisite principal amount of
Securities have consented (and not theretofore revoked such consent) to the
amendment, supplement or waiver.

         The Issuers may, but shall not be obligated to, fix a record date for
the purpose of determining the Holders entitled to consent to any amendment,
supplement or waiver which record date shall be at least 30 days prior to the
first solicitation of such consent. If a record date is fixed, then
notwithstanding the last sentence of the immediately preceding paragraph, those
Persons who were Holders at such record date (or their duly designated proxies),
and only those Persons, shall be entitled to revoke any consent previously
given, whether or not such Persons continue to be Holders after such record
date. No such consent shall be valid or effective for more than 90 days after
such record date.

         After an amendment, supplement or waiver becomes effective, it shall
bind every Securityholder, unless it makes a change described in any of clauses
(1) through (7) of Section 9.2, in which case, the amendment, supplement or
waiver shall bind only each Holder of a Security who has consented to it and
every subsequent Holder of a Security or portion of a Security that evidences
the same debt as the consenting Holder's Security; provided, that any such
waiver shall not impair or affect the right of any Holder to receive payment of
principal of and interest on a Security, on or after the respective due dates
expressed in such Security, or to bring suit for the enforcement of any such
payment on or after such respective dates without the consent of such Holder.

         Section 9.6 Notation on or Exchange of Securities. If an amendment,
supplement or waiver changes the terms of a Security, the Issuers may require
the Holder of the Security to deliver it to the Trustee. The Issuers shall
provide the Trustee with an appropriate notation on the Security about the
changed terms and cause the Trustee to return it to the Holder at the Issuers'
expense. Alternatively, if the Issuers or the Trustee so determine, in exchange
for the Security

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<PAGE>   77

the Issuers shall issue and the Trustee shall authenticate a new Security that
reflects the changed terms. Failure to make the appropriate notation or issue a
new Security shall not affect the validity and effect of such amendment,
supplement or waiver.

         Section 9.7 Trustee To Sign Amendments, Etc. The Trustee shall execute
any amendment, supplement or waiver authorized pursuant to this Article Nine;
provided, that the Trustee may, but shall not be obligated to, execute any such
amendment, supplement or waiver which affects the Trustee's own rights, duties
or immunities under this Indenture. The Trustee shall be entitled to receive,
and shall be fully protected in relying upon, an Opinion of Counsel and an
Officers' Certificate from each Issuer each stating that the execution of any
amendment, supplement or waiver authorized pursuant to this Article Nine is
authorized or permitted by this Indenture and constituted the legal, valid and
binding obligations of the Issuers enforceable in accordance with its terms.
Such Opinions of Counsel shall be at the expense of the Issuers.

                                   ARTICLE TEN

                           SUBORDINATION OF SECURITIES

         Section 10.1 Securities Subordinated to Senior Debt. Anything herein to
the contrary notwithstanding, each Issuer, for itself and its successors, and
each Holder, by his or her acceptance of Securities, agrees that the payment of
all obligations owing to the Holders in respect of the Securities is
subordinated, to the extent and in the manner provided in this Article Ten, to
the prior payment in full in cash or Cash Equivalents, or such payment duly
provided for to the satisfaction of the holders of Senior Debt, of all
obligations on Senior Debt (including the obligations with respect to the Senior
Secured Credit Agreement). Notwithstanding the foregoing, payments and
distributions made relating to the Securities pursuant to the trust described
under Article Eight shall not, so long as the conditions specified in Article
Eight (without any waiver or modification of the requirement that the deposits
pursuant thereto do not conflict with the terms of the Senior Secured Credit
Agreement or any other Senior Debt) are satisfied on the date of any deposit
pursuant to said trust, be so subordinated in right of payment.

         This Article Ten shall constitute a continuing offer to all Persons who
become holders of, or continue to hold, Senior Debt, and such provisions are
made for the benefit of the holders of Senior Debt and such holders are made
obligees hereunder and any one or more of them may enforce such provisions.

         Section 10.2 Suspension of Payment When Senior Debt Is in Default. (a)
If any default occurs and is continuing in the payment when due, whether at
maturity, upon any redemption, by declaration or otherwise, of any principal of,
interest on, unpaid drawings for letters of credit issued in respect of, or
regularly accruing fees with respect to, any Senior Debt (a "Payment Default"),
then no payment or distribution of any kind or character shall be made by or on
behalf of the Issuers or any other Person on behalf of any of them with respect
to any obligation on or relating to the Securities or to acquire any of the
Securities for cash or property or otherwise.

                  (b) If any other event of default (other than a Payment
Default) occurs and is continuing with respect to any Designated Senior Debt (as
such event of default is defined in the

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<PAGE>   78

instrument creating or evidencing such Designated Senior Debt) permitting the
holders of such Designated Senior Debt then outstanding to accelerate the
maturity thereof (a "Non-payment Default") and if the Representative for the
respective issue of Designated Senior Debt gives notice of the event of default
to the Trustee stating that such notice is a payment blockage notice (a "Payment
Blockage Notice"), then, unless and until all events of default have been cured
or waived or have ceased to exist or the Trustee receives notice thereof from
the Representative for the respective issue of Designated Senior Debt
terminating the Payment Blockage Period (as defined below), during the 180 days
after the delivery of such Payment Blockage Notice (the "Payment Blockage
Period"), neither the Issuers nor any other Person on their behalf shall (x)
make any payment of any kind or character with respect to any obligation on or
with respect to the Securities or (y) acquire any of the Securities for cash or
property or otherwise. Notwithstanding anything herein to the contrary, (x) in
no event will a Payment Blockage Period extend beyond 180 days from the date the
applicable Payment Blockage Notice is received by the Trustee and (y) only one
such Payment Blockage Period may be commenced within any period of 360
consecutive days. For all purposes of this Section 10.2(b), no event of default
which existed or was continuing on the date of the commencement of any Payment
Blockage Period with respect to the Designated Senior Debt shall be, or be made,
the basis for the commencement of a second Payment Blockage Period by the
Representative of such Designated Senior Debt whether or not within a period of
360 consecutive days, unless such event of default shall have been cured or
waived for a period of not less than 90 consecutive days (it being acknowledged
that any subsequent action, or any breach of any financial covenants for a
period commencing after the date of commencement of such Payment Blockage Period
that, in either case, would give rise to an event of default pursuant to any
provisions under which an event of default previously existed or was continuing
shall constitute a new event of default for this purpose).

                  (c) In the event that, notwithstanding the foregoing, any
payment shall be received by the Trustee or any Holder when such payment is
prohibited by the foregoing provisions of this Section 10.2, such payment shall
be held for the benefit of, and shall be paid over or delivered to, the holders
of Senior Debt (pro rata to such holders on the basis of the respective amount
of Senior Debt held by such holders) or their respective Representatives, as
their respective interests may appear. The Trustee shall be entitled to rely on
information regarding amounts then due and owing on the Senior Debt, if any,
received from the holders of Senior Debt (or their Representatives) or, if such
information is not received from such holders or their Representatives, from the
Issuers and only amounts included in the information provided to the Trustee
shall be paid to the holders of Senior Debt.

                  Nothing contained in this Article Ten shall limit the right of
the Trustee or the Holders of Securities to take any action to accelerate the
maturity of the Securities pursuant to Section 6.2 or to pursue any rights or
remedies hereunder; provided, that all Senior Debt thereafter due or declared to
be due shall first be paid in full in cash or Cash Equivalents before the
Holders are entitled to receive any payment of any kind or character with
respect to obligations on the Securities.

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<PAGE>   79

         Section 10.3 Securities Subordinated to Prior Payment of All Senior
Debt on Dissolution, Liquidation or Reorganization of an Issuer. (a) Upon any
payment or distribution of assets of the Issuers of any kind or character,
whether in cash, property or securities, to creditors upon any total or partial
liquidation, dissolution, winding-up, reorganization, assignment for the benefit
of creditors or marshaling of assets of an Issuer or in a bankruptcy,
reorganization, insolvency, receivership or other similar proceeding relating to
an Issuer or its property, whether voluntary or involuntary, all obligations due
or to become due upon all Senior Debt shall first be paid in full in cash or
Cash Equivalents, or such payment duly provided for to the satisfaction of the
holders of Senior Debt, before any payment or distribution of any kind or
character is made on account of any obligation on or relating to the Securities,
or for the acquisition of any of the Securities for cash or property or
otherwise. Upon any such dissolution, winding-up, liquidation, reorganization,
receivership or similar proceeding, any payment or distribution of assets of an
Issuer of any kind or character, whether in cash, property or securities, to
which the Holders of the Securities or the Trustee under this Indenture would be
entitled, except for the provisions hereof, shall be paid by such Issuer or by
any receiver, trustee in bankruptcy, liquidating trustee, agent or other Person
making such payment or distribution, or by the Holders or by the Trustee under
this Indenture if received by them, directly to the holders of Senior Debt (pro
rata to such holders on the basis of the respective amounts of Senior Debt held
by such holders) or their respective Representatives, or to the trustee or
trustees under any indenture pursuant to which any of such Senior Debt may have
been issued, as their respective interests may appear, for application to the
payment of Senior Debt remaining unpaid until all such Senior Debt has been paid
in full in cash or Cash Equivalents after giving effect to any concurrent
payment, distribution or provision therefor to or for the holders of Senior
Debt.

         (b) To the extent any payment of Senior Debt (whether by or on behalf
of an Issuer, as proceeds of security or enforcement of any right of setoff or
otherwise) is declared to be fraudulent or preferential, set aside or required
to be paid to any receiver, trustee in bankruptcy, liquidating trustee, agent or
other similar Person under any bankruptcy, insolvency, receivership, fraudulent
conveyance or similar law, then, if such payment is recovered by, or paid over
to, such receiver, trustee in bankruptcy, liquidating trustee, agent or other
similar Person, the Senior Debt or part thereof originally intended to be
satisfied shall be deemed to be reinstated and outstanding as if such payment
had not occurred.

         (c) In the event that, notwithstanding the foregoing, any payment or
distribution of assets of an Issuer of any kind or character, whether in cash,
property or securities, shall be received by any Holder when such payment or
distribution is prohibited by this Section 10.3, such payment or distribution
shall be held for the benefit of, and shall be paid over or delivered to, the
holders of Senior Debt (pro rata to such holders on the basis of the respective
amount of Senior Debt held by such holders) or their respective Representatives,
or to the trustee or trustees under any indenture pursuant to which any of such
Senior Debt may have been issued, as their respective interests may appear, for
application to the payment of Senior Debt remaining unpaid until all such Senior
Debt has been paid in full in cash or Cash Equivalents, after giving effect to
any concurrent payment, distribution or provision therefor to or for the holders
of such Senior Debt.

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<PAGE>   80

         (d) The consolidation of an Issuer with, or the merger of an Issuer
with or into, another corporation, partnership, trust or limited liability
company or the liquidation or dissolution of an Issuer following the conveyance
or transfer of all or substantially all of its assets, to another corporation,
partnership, trust or limited liability company upon the terms and conditions
provided in Article Five hereof and as long as permitted under the terms of the
Senior Debt shall not be deemed a dissolution, winding-up, liquidation or
reorganization for the purposes of this Section if such other corporation shall,
as a part of such consolidation, merger, conveyance or transfer, assume such
Issuer's obligations hereunder in accordance with Article Five hereof.

         Section 10.4 Payments May Be Paid Prior to Dissolution. Nothing
contained in this Article Ten or elsewhere in this Indenture shall prevent (i)
the Issuers, except under the conditions described in Sections 10.2 and 10.3,
from making payments at any time for the purpose of making payments of principal
of and interest on the Securities, or from depositing with the Trustee any
moneys for such payments, or (ii) in the absence of actual knowledge by the
Trustee that a given payment would be prohibited by Section 10.2 or 10.3, the
application by the Trustee of any moneys deposited with it for the purpose of
making such payments of principal of, and interest on, the Securities to the
Holders entitled thereto unless at least two Business Days prior to the date
upon which such payment would otherwise become due and payable a Trust Officer
shall have actually received the written notice provided for in the first
sentence of Section 10.2(b) or in Section 10.7 (provided, that notwithstanding
the foregoing, the Holders receiving any payments made in contravention of
Section 10.2 and/or 10.3 (and any such payments) shall otherwise be subject to
the provisions of Section 10.2 and Section 10.3). The Issuers shall give prompt
written notice to the Trustee of any dissolution, winding-up, liquidation or
reorganization of the Issuers, although any delay or failure to give any such
notice shall have no effect on the subordination provisions contained herein.

         Section 10.5 Holders To Be Subrogated to Rights of Holders of Senior
Debt. Subject to the payment in full in cash or Cash Equivalents of all Senior
Debt, the Holders of the Securities shall be subrogated to the rights of the
holders of Senior Debt to receive payments or distributions of cash, property or
securities of the Issuers applicable to the Senior Debt until the Securities
shall be paid in full; and, for the purposes of such subrogation, no such
payments or distributions to the holders of the Senior Debt by or on behalf of
the Issuers, or by or on behalf of the Holders by virtue of this Article Ten,
which otherwise would have been made to the Holders shall, as between the
Issuers and the Holders, be deemed to be a payment by the Issuers to or on
account of the Senior Debt, it being understood that the provisions of this
Article Ten are and are intended solely for the purpose of defining the relative
rights of the Holders, on the one hand, and the holders of Senior Debt, on the
other hand.

         Section 10.6 Obligation of the Issuers Unconditional. Nothing contained
in this Article Ten or elsewhere in this Indenture or in the Securities is
intended to or shall impair, as among the Issuers, their creditors other than
the holders of Senior Debt, and the Holders, the obligation of the Issuers,
which is absolute and unconditional, to pay to the Holders the principal of and
any interest on the Securities as and when the same shall become due and payable
in accordance with their terms, or is intended to or shall affect the relative
rights of the Holders and creditors of the Issuers other than the holders of the
Senior Debt, nor shall anything herein or therein prevent the

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<PAGE>   81

Holder of any Security or the Trustee on its behalf from exercising all remedies
otherwise permitted by applicable law upon default under this Indenture, subject
to the rights, if any, in respect of cash, property or securities of the Issuers
received upon the exercise of any such remedy.

         Section 10.7 Notice to Trustee. Each Issuer shall give prompt written
notice to the Trustee of any fact known to such Issuer which would prohibit the
making of any payment to or by the Trustee in respect of the Securities pursuant
to the provisions of this Article Ten, although any delay or failure to give any
such notice shall have no effect on the subordination provisions contained
herein. Regardless of anything to the contrary contained in this Article Ten or
elsewhere in this Indenture, the Trustee shall not be charged with knowledge of
the existence of any default or event of default with respect to any Senior Debt
or of any other facts which would prohibit the making of any payment to or by
the Trustee unless and until the Trustee shall have received notice in writing
from an Issuer, or from a holder of Senior Debt or a Representative therefor
and, prior to the receipt of any such written notice, the Trustee shall be
entitled to assume (in the absence of actual knowledge to the contrary) that no
such facts exist. The Trustee shall be entitled to rely on the delivery to it of
any notice pursuant to this Section 10.7 to establish that such notice has been
given by a holder of Senior Debt (or a trustee thereof).

         In the event that the Trustee determines in good faith that any
evidence is required with respect to the right of any Person as a holder of
Senior Debt to participate in any payment or distribution pursuant to this
Article Ten, the Trustee may request such Person to furnish evidence to the
reasonable satisfaction of the Trustee as to the amounts of Senior Debt held by
such Person, the extent to which such Person is entitled to participate in such
payment or distribution and any other facts pertinent to the rights of such
Person under this Article Ten, and if such evidence is not furnished the Trustee
may defer any payment to such Person pending judicial determination as to the
right of such Person to receive such payment.

         Section 10.8 Reliance on Judicial Order or Certificate of Liquidating
Agent. Upon any payment or distribution of assets of an Issuer referred to in
this Article Ten, the Trustee, subject to the provisions of Article Seven
hereof, and the Holders of the Securities shall be entitled to rely upon any
order or decree made by any court of competent jurisdiction in which any
insolvency, bankruptcy, receivership, dissolution, winding-up, liquidation,
reorganization or similar case or proceeding is pending, or upon a certificate
of the receiver, trustee in bankruptcy, liquidating trustee, assignee for the
benefit of creditors, agent or other person making such payment or distribution,
delivered to the Trustee or the Holders of the Securities, for the purpose of
ascertaining the persons entitled to participate in such payment or
distribution, the holders of the Senior Debt and other Indebtedness of the
Issuers, the amount thereof or payable thereon, the amount or amounts paid or
distributed thereon and all other facts pertinent thereto or to this Article
Ten.

         Section 10.9 Trustee's Relation to Senior Debt. The Trustee and any
agent of an Issuer or the Trustee shall be entitled to all the rights set forth
in this Article Ten with respect to any Senior Debt which may at any time be
held by it in its individual or any other capacity to the

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<PAGE>   82
same extent as any other holder of Senior Debt and nothing in this Indenture
shall deprive the Trustee or any such agent of any of its rights as such holder.

         With respect to the holders of Senior Debt, the Trustee undertakes to
perform or to observe only such of its covenants and obligations as are
specifically set forth in this Article Ten, and no implied covenants or
obligations with respect to the holders of Senior Debt shall be read into this
Indenture against the Trustee. The Trustee shall not be deemed to owe any
fiduciary duty to the holders of Senior Debt.

         Whenever a distribution is to be made or a notice given to holders or
owners of Senior Debt, the distribution may be made and the notice may be given
to their Representative, if any.

         Section 10.10 Subordination Rights Not Impaired by Acts or Omissions of
an Issuer or Holders of Senior Debt. No right of any present or future holders
of any Senior Debt to enforce subordination as provided herein shall at any time
in any way be prejudiced or impaired by any act or failure to act on the part of
an Issuer or by any act or failure to act, in good faith, by any such holder, or
by any noncompliance by an Issuer with the terms of this Indenture, regardless
of any knowledge thereof which any such holder may have or otherwise be charged
with.

         Without in any way limiting the generality of the foregoing paragraph,
the holders of Senior Debt may, at any time and from time to time, without the
consent of or notice to the Trustee, without incurring responsibility to the
Trustee or the Holders of the Securities and without impairing or releasing the
subordination provided in this Article Ten or the obligations hereunder of the
Holders of the Securities to the holders of the Senior Debt, do any one or more
of the following: (i) change the manner, place or terms of payment or extend the
time of payment of, or renew or alter, Senior Debt, or otherwise amend or
supplement in any manner Senior Debt, or any instrument evidencing the same or
any agreement under which Senior Debt is outstanding; (ii) sell, exchange,
release or otherwise deal with any property pledged, mortgaged or otherwise
securing Senior Debt; (iii) release any Person liable in any manner for the
payment or collection of Senior Debt; and (iv) exercise or refrain from
exercising any rights against the Issuers and any other Person.

         Section 10.11 Securityholders Authorize Trustee To Effectuate
Subordination of Securities. Each Holder of Securities by its acceptance thereof
authorizes and expressly directs the Trustee on its behalf to take such action
as may be necessary or appropriate to effectuate, as between the holders of
Senior Debt and the Holders of Securities, the subordination provided in this
Article Ten, and appoints the Trustee its attorney-in-fact for such purposes,
including, in the event of any dissolution, winding-up, liquidation or
reorganization of an Issuer (whether in bankruptcy, insolvency, receivership,
reorganization or similar proceedings or upon an assignment for the benefit of
credits or otherwise) tending towards liquidation of the business and assets of
an Issuer, the filing of a claim for the unpaid balance of its Securities and
accrued interest in the form required in those proceedings.

         If the Trustee does not file a proper claim or proof of debt in the
form required in such proceeding prior to 30 days before the expiration of the
time to file such claim or claims, then the holders of the Senior Debt or its
Representative are or is hereby authorized to have the right to

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<PAGE>   83

file and are or is hereby authorized to file an appropriate claim for and on
behalf of the Holders of said Securities. Nothing herein contained shall be
deemed to authorize the Trustee or any holder of Senior Debt or its
Representative to authorize or consent to or accept or adopt on behalf of any
Holder any plan of reorganization, arrangement, adjustment or composition
affecting the Securities or the rights of any Holder thereof, or to authorize
the Trustee or the holders of Senior Debt or their Representative to vote in
respect of the claim of any Holder in any such proceeding.

         Section 10.12 This Article Ten Not To Prevent Events of Default. The
failure to make a payment on account of principal of or interest on the
Securities by reason of any provision of this Article Ten will not be construed
as preventing the occurrence of an Event of Default.

         Section 10.13 Trustee's Compensation Not Prejudiced. Nothing in this
Article Ten will apply to amounts due to the Trustee pursuant to other sections
of this Indenture.

                                 ARTICLE ELEVEN

                             GUARANTEE OF SECURITIES

         Section 11.1 Unconditional Guarantee. Subject to the provisions of this
Article Eleven, each of the Guarantors hereby, jointly and severally,
unconditionally and irrevocably guarantees, on a senior subordinated basis (such
guarantees to be referred to herein as a "Guarantee") to each Holder of a
Security authenticated and delivered by the Trustee and to the Trustee and its
successors and assigns, irrespective of the validity and enforceability of this
Indenture, the Securities or the obligations of the Issuers or any other
Guarantors to the Holders or the Trustee hereunder or thereunder, that: (a) the
principal of, premium, if any, and interest on the Securities shall be duly and
punctually paid in full when due, whether at maturity, upon redemption at the
option of Holders pursuant to the provisions of the Securities relating thereto,
by acceleration or otherwise, and interest on the overdue principal and (to the
extent permitted by law) interest, if any, on the Securities and all other
obligations of the Issuers or the Guarantors to the Holders or the Trustee
hereunder or thereunder (including amounts due the Trustee under Section 7.7
hereof) and all other obligations shall be promptly paid in full or performed,
all in accordance with the terms hereof and thereof; and (b) in case of any
extension of time of payment or renewal of any Securities or any of such other
obligations, the same shall be promptly paid in full when due or performed in
accordance with the terms of the extension or renewal, whether at maturity, by
acceleration or otherwise. Failing payment when due of any amount so guaranteed,
or failing performance of any other obligation of the Issuers to the Holders
under this Indenture or under the Securities, for whatever reason, each
Guarantor shall be obligated to pay, or to perform or cause the performance of,
the same immediately. An Event of Default under this Indenture or the Securities
shall constitute an event of default under this Guarantee, and shall entitle the
Holders of Securities to accelerate the obligations of the Guarantors hereunder
in the same manner and to the same extent as the obligations of the Issuers.

         Each of the Guarantors hereby agrees that its obligations hereunder
shall be unconditional, irrespective of the validity, regularity or
enforceability of the Securities or this Indenture, the absence of any action to
enforce the same, any waiver or consent by any Holder of

                                      -79-
<PAGE>   84

the Securities with respect to any provisions hereof or thereof, any release of
any other Guarantor, the recovery of any judgment against an Issuer, any action
to enforce the same, whether or not a Guarantee is affixed to any particular
Security, or any other circumstance which might otherwise constitute a legal or
equitable discharge or defense of a Guarantor. Each of the Guarantors hereby
waives the benefit of diligence, presentment, demand of payment, filing of
claims with a court in the event of insolvency or bankruptcy of an Issuer, any
right to require a proceeding first against an Issuer, protest, notice and all
demands whatsoever and covenants that its Guarantee shall not be discharged
except by complete performance of the obligations contained in the Securities,
this Indenture and this Guarantee. This Guarantee is a guarantee of payment and
not of collection. If any Holder or the Trustee is required by any court or
otherwise to return to the Issuers or to any Guarantor, or any custodian,
trustee, liquidator or other similar official acting in relation to an Issuer or
such Guarantor, any amount paid by an Issuer or such Guarantor to the Trustee or
such Holder, this Guarantee, to the extent theretofore discharged, shall be
reinstated in full force and effect. Each Guarantor further agrees that, as
between it, on the one hand, and the Holders of Securities and the Trustee, on
the other hand, (a) subject to this Article Eleven, the maturity of the
obligations guaranteed hereby may be accelerated as provided in Article Six
hereof for the purposes of this Guarantee, notwithstanding any stay, injunction
or other prohibition preventing such acceleration in respect of the obligations
guaranteed hereby, and (b) in the event of any acceleration of such obligations
as provided in Article Six hereof, such obligations (whether or not due and
payable) shall forthwith become due and payable by the Guarantors for the
purpose of this Guarantee.

         No stockholder, officer, director, employee or incorporator, past,
present or future, or any Guarantor, as such, shall have any personal liability
under this Guarantee by reason of his, her or its status as such stockholder,
officer, director, employee or incorporator.

         Each Guarantor that makes a payment or distribution under a Guarantee
shall be entitled to a contribution from each other Guarantor on a pro rata
basis, based on the net assets of each Guarantor, determined in accordance with
GAAP.

         Section 11.2 Limitations on Guarantees. The Obligations of each
Guarantor under its Guarantee are limited to the maximum amount which, after
giving effect to all other contingent and fixed liabilities of such Guarantor
(including without limitation, its guarantee of obligations in respect of the
Senior Secured Credit Agreement and any other Guarantor Senior Debt) and after
giving effect to any collections from or payments made by or on behalf of any
other Guarantor in respect of the obligations of such other Guarantor under its
Guarantee or pursuant to its contribution obligations under this Indenture, will
result in the obligations of such Guarantor under the Guarantee not constituting
a fraudulent conveyance or fraudulent transfer under federal or state law.

         Section 11.3 Execution and Delivery of Guarantee. To further evidence
the Guarantee set forth in Section 11.1, each Guarantor hereby agrees that a
notation of such Guarantee, substantially in the form of Exhibit E, shall be
endorsed on each Security authenticated and delivered by the Trustee. Such
Guarantee shall be executed on behalf of each Guarantor by either manual or
facsimile signature of one Officer of each Guarantor who shall have been duly

                                      -80-
<PAGE>   85

authorized to so execute by all requisite corporation action. The validity and
enforceability of any Guarantee shall not be affected by the fact that it is not
affixed to any particular Security.

         Each of the Guarantors hereby agrees that its Guarantee set forth in
Section 11.1 shall remain in full force and effect notwithstanding any failure
to endorse on each Security a notation of such Guarantee.

         If an Officer of a Guarantor whose signature is on this Indenture or a
Guarantee no longer holds that office at the time the Trustee authenticates the
Security on which such Guarantee is endorsed or at any time thereafter, such
Guarantor's Guarantee of such Security shall nevertheless be valid.

         The delivery of any Security by the Trustee, after the authentication
thereof hereunder, shall constitute due delivery of any Guarantee set forth in
this Indenture on behalf of each Guarantor.

         Section 11.4 Release of a Guarantor. (a) Upon the sale or disposition
of all of the Capital Stock of a Guarantor by an Issuer, in a transaction or
series of related transactions that either (i) does not constitute an Asset Sale
or (ii) constitutes an Asset Sale the Net Cash Proceeds of which are applied in
accordance with Section 4.16, or upon the consolidation or merger of a Guarantor
(other than Parent) with or into any Person in compliance with Article Five (in
each case, other than to or into an Issuer or an Affiliate of an Issuer), or if
any Guarantor is dissolved or liquidated in accordance with this Indenture, such
Guarantor's Guarantee will be automatically discharged and released from all
obligations under this Article Eleven without any further action required on the
part of the Trustee or any Holder. Any Guarantor not so released or the entity
surviving such Guarantor, as applicable, shall remain or be liable under its
Guarantee as provided in this Article Eleven.

         (b) The Trustee shall deliver an appropriate instrument evidencing the
release of a Guarantor prepared by the Issuers or such Guarantor upon receipt of
a request by the Issuers or such Guarantor accompanied by an Officers'
Certificate and an Opinion of Counsel certifying compliance with this Section
11.4; provided, that the legal counsel delivering such Opinion of Counsel may
rely as to matters of fact on Officers' Certificates of the Issuers.

         The Trustee shall execute any documents reasonably requested by the
Issuers or a Guarantor in order to evidence the release of such Guarantor from
its obligations under its Guarantee endorsed on the Securities and under this
Article Eleven.

         Except as set forth in Articles Four and Five and this Section 11.4,
nothing contained in this Indenture or in any of the Securities shall prevent
any consolidation or merger of a Guarantor (other than Parent) with or into an
Issuer or another Guarantor or shall prevent any sale or conveyance of the
property of a Guarantor (other than Parent) as an entirety or substantially as
an entirety to an Issuer or another Guarantor.

         (c) Notwithstanding the foregoing, the Guarantee of Parent may not be
released.

                                      -81-
<PAGE>   86

         Section 11.5 Waiver of Subrogation. Until this Indenture is discharged
and all of the Securities are discharged and paid in full, each Guarantor hereby
irrevocably waives and agrees not to exercise any claim or other rights which it
may now or hereafter acquire against an Issuer that arise from the existence,
payment, performance or enforcement of such Issuer's obligations under the
Securities or this Indenture and such Guarantor's obligations under this
Guarantee and this Indenture, in any such instance including, without
limitation, any right of subrogation, reimbursement, exoneration, contribution,
indemnification, and any right to participate in any claim or remedy of the
Holders against an Issuer, whether or not such claim, remedy or right arises in
equity, or under contract, statute or common law, including, without limitation,
the right to take or receive from an Issuer, directly or indirectly, in cash or
other property or by set-off or in any other manner, payment or security on
account of such claim or other rights. If any amount shall be paid to any
Guarantor in violation of the preceding sentence and any amounts owing to the
Trustee or the Holders of Securities under the Securities, this Indenture, or
any other document or instrument delivered under or in connection with such
agreements or instruments, shall not have been paid in full, such amount shall
have been deemed to have been paid to such Guarantor for the benefit of, and
held in trust for the benefit of, the Trustee or the Holders and shall forthwith
be paid to the Trustee for the benefit of itself or such Holders to be credited
and applied to the obligations in favor of the Trustee or the Holders, as the
case may be, whether matured or unmatured, in accordance with the terms of this
Indenture. Each Guarantor acknowledges that it will receive direct and indirect
benefits from the financing arrangements contemplated by this Indenture and that
the waiver set forth in this Section 11.5 is knowingly made in contemplation of
such benefits.

         Section 11.6 Immediate Payment. Each Guarantor agrees to make immediate
payment to the Trustee on behalf of the Holders of all obligations in respect of
the Securities owing or payable to the respective Holders upon receipt of a
demand for payment therefor by the Trustee to such Guarantor in writing.

         Section 11.7 No Set-Off. Each payment to be made by a Guarantor
hereunder in respect of the obligations in respect of the Securities shall be
payable in the currency or currencies in which such obligations are denominated,
and shall be made without set-off, counterclaim, reduction or diminution of any
kind or nature.

         Section 11.8 Obligations Absolute. The obligations of each Guarantor
hereunder are and shall be absolute and unconditional and any monies or amounts
expressed to be owing or payable by each Guarantor hereunder which may not be
recoverable from such Guarantor on the basis of a Guarantee shall be recoverable
from such Guarantor as a primary obligor and principal debtor in respect
thereof.

         Section 11.9 Obligations Continuing. The obligations of each Guarantor
hereunder shall be continuing and shall remain in full force and effect until
all the obligations have been paid and satisfied in full. Each Guarantor agrees
with the Trustee that it will from time to time deliver to the Trustee suitable
acknowledgments of this continued liability hereunder and under any other
instrument or instruments in such form as counsel to the Trustee may advise and
as will prevent any action brought against it in respect of any default
hereunder being barred by any statute of

                                      -82-
<PAGE>   87

limitations now or hereafter in force and, in the event of the failure of a
Guarantor so to do, it hereby irrevocably appoints the Trustee the attorney and
agent of such Guarantor to make, execute and deliver such written acknowledgment
or acknowledgments or other instruments as may from time to time become
necessary or advisable, in the judgment of the Trustee on the advice of counsel,
to fully maintain and keep in force the liability of such Guarantor hereunder.

         Section 11.10 Obligations Not Reduced. The obligations of each
Guarantor hereunder shall not be satisfied, reduced or discharged solely by the
payment of such principal, premium, if any, interest, fees and other monies or
amounts as may at any time prior to discharge of this Indenture pursuant to
Article Eight be or become owing or payable under or by virtue of or otherwise
in connection with the Securities or this Indenture.

         Section 11.11 Obligations Reinstated. The obligations of each Guarantor
hereunder shall continue to be effective or shall be reinstated, as the case may
be, if at any time any payment which would otherwise have reduced the
obligations of any Guarantor hereunder (whether such payment shall have been
made by or on behalf of an Issuer or by or on behalf of a Guarantor) is
rescinded or reclaimed from any of the Holders upon the insolvency, bankruptcy,
liquidation or reorganization of an Issuer or any Guarantor or otherwise, all as
though such payment had not been made. If demand for, or acceleration of the
time for, payment by an Issuer is stayed upon the insolvency, bankruptcy,
liquidation or reorganization of an Issuer, all such Indebtedness otherwise
subject to demand for payment or acceleration shall nonetheless be payable by
each Guarantor as provided herein.

         Section 11.12 Obligations Not Affected. The obligations of each
Guarantor hereunder shall not be affected, impaired or diminished in any way by
any act, omission, matter or thing whatsoever, occurring before, upon or after
any demand for payment hereunder (and whether or not known or consented to by
any Guarantor or any of the Holders) which, but for this provision, might
constitute a whole or partial defense to a claim against any Guarantor hereunder
or might operate to release or otherwise exonerate any Guarantor from any of its
obligations hereunder or otherwise affect such obligations, whether occasioned
by default of any of the Holders or otherwise, including, without limitation:

         (a) any limitation of status or power, disability, incapacity or other
circumstance relating to an Issuer or any other Person, including any
insolvency, bankruptcy, liquidation, reorganization, readjustment, composition,
dissolution, winding-up or other proceeding involving or affecting an Issuer or
any other Person;

         (b) any irregularity, defect, unenforceability or invalidity in respect
of any indebtedness or other obligation of an Issuer or any other Person under
this Indenture, the Securities or any other document or instrument;

         (c) any failure of an Issuer, whether or not without fault on its part,
to perform or comply with any of the provisions of this Indenture or the
Securities, or to give notice thereof to a Guarantor;

                                      -83-
<PAGE>   88

         (d) the taking or enforcing or exercising or the refusal or neglect to
take or enforce or exercise any right or remedy from or against an Issuer or any
other Person or their respective assets or the release or discharge of any such
right or remedy;

         (e) the granting of time, renewals, extensions, compromises,
concessions, waivers, releases, discharges and other indulgences to an Issuer or
any other Person;

         (f) any change in the time, manner or place of payment of, or in any
other term of, any of the Securities, or any other amendment, variation,
supplement, replacement or waiver of, or any consent to departure from, any of
the Securities or this Indenture, including, without limitation, any increase or
decrease in the principal amount of or premium, if any, or interest on any of
the Securities;

         (g) any change in the ownership, control, name, objects, businesses,
assets, capital structure or constitution of an Issuer or a Guarantor;

         (h) any merger or amalgamation of an Issuer or a Guarantor with any
Person or Persons;

         (i) the occurrence of any change in the laws, rules, regulations or
ordinances of any jurisdiction by any present or future action of any
governmental authority or court amending, varying, reducing or otherwise
affecting, or purporting to amend, vary, reduce or otherwise affect, any of the
Obligations in respect of the Securities or the obligations of a Guarantor under
its Guarantee; and

         (j) any other circumstance, including release of the Guarantor pursuant
to Section 11.4 (other than by complete, irrevocable payment) that might
otherwise constitute a legal or equitable discharge or defense of an Issuer
under this Indenture or the Securities or of a Guarantor in respect of its
Guarantee hereunder.

         Section 11.13 Waiver. Without in any way limiting the provisions of
Section 11.1 hereof, each Guarantor hereby waives notice of acceptance hereof,
notice of any liability of any Guarantor hereunder, notice or proof of reliance
by the Holders upon the obligations of any Guarantor hereunder, and diligence,
presentment, demand for payment on any Issuer, protest, notice of dishonor or
non-payment of any of the Obligations, in respect of the securities or other
notice or formalities to any Issuer or any Guarantor of any kind whatsoever.

         Section 11.14 No Obligation To Take Action Against the Issuers. Neither
the Trustee nor any other Person shall have any obligation to enforce or exhaust
any rights or remedies or to take any other steps under any security for the
Obligations or against any Issuer or any other Person or any property of any
Issuer or any other Person before the Trustee is entitled to demand payment and
performance by any or all Guarantors of their liabilities and obligations under
their Guarantees or under this Indenture.

                                      -84-
<PAGE>   89

         Section 11.15 Dealing with the Issuers and Others. The Holders, without
releasing, discharging, limiting or otherwise affecting in whole or in part the
obligations and liabilities of any Guarantor hereunder and without the consent
of or notice to any Guarantor, may

         (a) grant time, renewals, extensions, compromises, concessions,
waivers, releases, discharges and other indulgences to an Issuer or any other
Person;

         (b) take or abstain from taking security or collateral from an Issuer
or from perfecting security or collateral of an Issuer;

         (c) release, discharge, compromise, realize, enforce or otherwise deal
with or do any act or thing in respect of (with or without consideration) any
and all collateral, mortgages or other security given by an Issuer or any third
party with respect to the obligations or matters contemplated by this Indenture
or the Securities;

         (d)  accept compromises or arrangements from an Issuer;

         (e) apply all monies at any time received from an Issuer or from any
security upon such part of the Issuers' obligations in respect of the Securities
as the Holders may see fit or change any such application in whole or in part
from time to time as the Holders may see fit; and

         (f) otherwise deal with, or waive or modify their right to deal with,
an Issuer and all other Persons and any security as the Holders or the Trustee
may see fit.

         Section 11.16 Default and Enforcement. If any Guarantor fails to pay in
accordance with Section 11.6 hereof, the Trustee may proceed in its name as
trustee hereunder in the enforcement of the Guarantee of any such Guarantor and
such Guarantor's obligations thereunder and hereunder by any remedy provided by
law, whether by legal proceedings or otherwise, and to recover from such
Guarantor the obligations.

         Section 11.17 Amendment, Etc. No amendment, modification or waiver of
any provision of this Indenture relating to any Guarantor or consent to any
departure by any Guarantor or any other Person from any such provision will in
any event be effective unless it is signed by such Guarantor and the Trustee.

         Section 11.18 Acknowledgment. Each Guarantor hereby acknowledges
communication of the terms of this Indenture and the Securities and consents to
and approves of the same.

         Section 11.19 Costs and Expenses. Each Guarantor shall pay on demand by
the Trustee any and all costs, fees and expenses (including, without limitation,
legal fees on a solicitor and client basis) incurred by the Trustee, its agents,
advisors and counsel or any of the Holders in enforcing any of their rights
under any Guarantee.

         Section 11.20 No Merger or Waiver; Cumulative Remedies. No Guarantee
shall operate by way of merger of any of the obligations of a Guarantor under
any other agreement, including, without limitation, this Indenture. No failure
to exercise and no delay in exercising, on the part of

                                      -85-
<PAGE>   90

the Trustee or the Holders, any right, remedy, power or privilege hereunder or
under this Indenture or the Securities, shall operate as a waiver thereof; nor
shall any single or partial exercise of any right, remedy, power or privilege
hereunder or under this Indenture or the Securities preclude any other or
further exercise thereof or the exercise of any other right, remedy, power or
privilege. The rights, remedies, powers and privileges in the Guarantee and
under this Indenture, the Securities and any other document or instrument
between a Guarantor and/or any Issuer and the Trustee are cumulative and not
exclusive of any rights, remedies, powers and privilege provided by law.

         Section 11.21 Survival of Obligations. Without prejudice to the
survival of any of the other obligations of each Guarantor hereunder, the
obligations of each Guarantor under Section 11.1 shall survive the payment in
full of the obligations of the Issuers in respect of the Securities and shall be
enforceable against such Guarantor without regard to and without giving effect
to any defense, right of offset or counterclaim available to or which may be
asserted by any Issuer or any Guarantor.

         Section 11.22 Guarantee in Addition to Other Obligations. The
obligations of each Guarantor under its Guarantee and this Indenture are in
addition to and not in substitution for any other obligations to the Trustee or
to any of the Holders in relation to this Indenture or the Securities and any
guarantees or security at any time held by or for the benefit of any of them.

         Section 11.23 Severability. Any provision of this Article Eleven which
is prohibited or unenforceable in any jurisdiction shall not invalidate the
remaining provisions and any such prohibition or unenforceability in any
jurisdiction shall not invalidate or render unenforceable such provision in any
other jurisdiction unless its removal would substantially defeat the basic
intent, spirit and purpose of this Indenture and this Article Eleven.

         Section 11.24 Successors and Assigns. Each Guarantee shall be binding
upon and inure to the benefit of each Guarantor and the Trustee and the other
Holders and their respective successors and permitted assigns, except that no
Guarantor may assign any of its obligations hereunder or thereunder.

                                      -86-
<PAGE>   91

                                 ARTICLE TWELVE

                           SUBORDINATION OF GUARANTEE

         Section 12.1 Guarantee Obligations Subordinated to Guarantor Senior
Debt. Anything herein to the contrary notwithstanding, each of the Guarantors,
for itself and its successors, and each Holder, by his or her acceptance of
Guarantees, agrees that the payment of all obligations owing to the Holders in
respect of its Guarantee (collectively, as to any Guarantor, its "Guarantee
Obligations") is subordinated, to the extent and in the manner provided in this
Article Twelve, to the prior payment in full in cash or Cash Equivalents, or
such payment duly provided for to the satisfaction of the holders of Guarantor
Senior Debt, of all obligations on Guarantor Senior Debt of such Guarantor.

         This Article Twelve shall constitute a continuing offer to all Persons
who become holders of, or continue to hold, Guarantor Senior Debt, and such
provisions are made for the benefit of the holders of Guarantor Senior Debt and
such holders are made obligees hereunder and any one or more of them may enforce
such provisions.

         Section 12.2 Suspension of Guarantee Obligations When Guarantor Senior
Debt Is in Default. (a) If any default occurs and is continuing in the payment
when due, whether at maturity, upon any redemption, by declaration or otherwise,
of any principal of, interest on, unpaid drawings for letters of credit issued
in respect of, or regularly accruing fees with respect to, any Guarantor Senior
Debt, then no payment of any kind or character shall be made by or on behalf of
such Guarantor or any other Person on its behalf with respect to any Guarantee
Obligations or to acquire any of the Securities for cash or property or
otherwise and until such Payment Default shall have been cured or waived or
shall have ceased to exist or such Guarantor Senior Debt shall have been
discharged or paid in full in cash or Cash Equivalents.

         (b) At any time while any Payment Blockage Period is in existence,
neither any Guarantor nor any other Person on any Guarantor's behalf shall (x)
make any payment of any kind or character with respect to any obligations on its
Guarantee or (y) acquire any of the Securities for cash or otherwise.

         (c) In the event that, notwithstanding the foregoing, any payment shall
be received by the Trustee or any Holder when such payment is prohibited by the
foregoing provisions of this Section 12.2, such payment shall be held for the
benefit of, and shall be paid over or delivered to, the holders of Guarantor
Senior Debt (pro rata to such holders on the basis of the respective amount of
Guarantor Senior Debt held by such holders) or their respective Representatives,
as their respective interests may appear. The Trustee shall be entitled to rely
on information regarding amounts then due and owing on the Guarantor Senior
Debt, if any, received from the holders of Guarantor Senior Debt (or their
Representatives) or, if such information is not received from such holders or
their Representatives, from a Guarantor and only amounts included in the
information provided to the Trustee shall be paid to the holders of Guarantor
Senior Debt.

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<PAGE>   92

         Section 12.3 Guarantee Obligations Subordinated to Prior Payment of All
Guarantor Senior Debt on Dissolution, Liquidation or Reorganization of Such
Guarantor. (a) Upon any payment or distribution of assets of any Guarantor of
any kind or character, whether in cash, property or securities, to creditors
upon any total or partial liquidation, dissolution, winding-up, reorganization,
assignment for the benefit of creditors or marshaling of assets of such
Guarantor or in a bankruptcy, reorganization, insolvency, receivership or other
similar proceeding relating to such Guarantor or its property, whether voluntary
or involuntary, all obligations due or to become due upon all Guarantor Senior
Debt shall first be paid in full in cash or Cash Equivalents, or such payment
duly provided for to the satisfaction of the holders of Guarantor Senior Debt,
before any payment or distribution of any kind or character is made on account
of any Guarantee Obligations or for the acquisition of any of the Securities for
cash or property or otherwise. Upon any such dissolution, winding-up,
liquidation, reorganization, receivership or similar proceeding, any payment or
distribution of assets of such Guarantor of any kind or character, whether in
cash, property or securities, to which the Holders or the Trustee under this
Indenture would be entitled, except for the provisions hereof, shall be paid by
such Guarantor or by any receiver, trustee in bankruptcy, liquidating trustee,
agent or other Person making such payment or distribution, or by the Holders or
by the Trustee under this Indenture if received by them, directly to the holders
of Guarantor Senior Debt (pro rata to such holders on the basis of the
respective amounts of Guarantor Senior Debt held by such holders) or their
respective Representatives, or to the trustee or trustees under any indenture
pursuant to which any of such Guarantor Senior Debt may have been issued, as
their respective interests may appear, for application to the payment of
Guarantor Senior Debt remaining unpaid until all such Guarantor Senior Debt has
been paid in full in cash or Cash Equivalents after giving effect to any
concurrent payment, distribution or provision therefor to or for the holders of
Guarantor Senior Debt.

         (b) To the extent any payment of Guarantor Senior Debt (whether by or
on behalf of a Guarantor, as proceeds of security or enforcement of any right of
setoff or otherwise) is declared to be fraudulent or preferential, set aside or
required to be paid to any receiver, trustee in bankruptcy, liquidating trustee,
agent or other similar Person under any bankruptcy, insolvency, receivership,
fraudulent conveyance or similar law, then, if such payment is recovered by, or
paid over to, such receiver, trustee in bankruptcy, liquidating trustee, agent
or other similar Person, the Guarantor Senior Debt or part thereof originally
intended to be satisfied shall be deemed to be reinstated and outstanding as if
such payment had not occurred.

         (c) In the event that, notwithstanding the foregoing, any payment or
distribution of assets of the Issuers of any kind or character, whether in cash,
property or securities, shall be received by any Holder when such payment or
distribution is prohibited by this Section 12.3, such payment or distribution
shall be held for the benefit of, and shall be paid over or delivered to, the
holders of Guarantor Senior Debt (pro rata to such holders on the basis of the
respective amount of Guarantor Senior Debt held by such holders) or their
respective Representatives, or to the trustee or trustees under any indenture
pursuant to which any of such Guarantor Senior Debt may have been issued, as
their respective interests may appear, for application to the payment of
Guarantor Senior Debt remaining unpaid until all such Guarantor Senior Debt has
been paid in

                                      -88-
<PAGE>   93

full in cash or Cash Equivalents, after giving effect to any concurrent payment,
distribution or provision therefor to or for the holders of such Guarantor
Senior Debt.

         (d) The consolidation of any Guarantor with, or the merger of any
Guarantor with or into, another corporation or the liquidation or dissolution of
a Guarantor following the conveyance or transfer of all or substantially all of
its assets to another corporation upon the terms and conditions provided in
Article Five hereof, and as long as permitted under the terms of the Guarantor
Senior Debt shall not be deemed a dissolution, winding-up, liquidation or
reorganization for the purposes of this Section 12.3 if such other corporation
shall, as a part of such consolidation, merger, conveyance or transfer, assumes
the Guarantee of such Guarantor hereunder in accordance with Article Five
hereof.

         Section 12.4 Payments May Be Paid Prior to Dissolution. Nothing
contained in this Article Twelve or elsewhere in this Indenture shall prevent
(i) any Guarantor, except under the conditions described in Sections 12.2 and
12.3, from making payments at any time for the purpose of making payments on
Guarantee Obligations, or from depositing with the Trustee any moneys for such
payments, or (ii) in the absence of actual knowledge by the Trustee that a given
payment would be prohibited by Section 12.2 or 12.3, the application by the
Trustee of any moneys deposited with it for the purpose of making such payments
on Guarantee Obligations to the Holders entitled thereto unless at least two
Business Days prior to the date upon which such payment would otherwise become
due and payable a Trust Officer shall have actually received the written notice
provided for in the first sentence of Section 10.2(b) or in Section 12.7
(provided, that notwithstanding the foregoing, the Holders receiving any
payments made in contravention of Sections 12.2 and/or 12.3 (and any such
payments) shall otherwise be subject to the provisions of Section 12.2 and
Section 12.3). Each Guarantor shall give prompt written notice to the Trustee of
any dissolution, winding-up, liquidation or reorganization of such Guarantor,
although any delay or failure to give any such notice shall have no effect on
the subordination provisions contained herein.

         Section 12.5 Holders of Guarantee Obligations To Be Subrogated to
Rights of Holders of Guarantor Senior Debt. Subject to the payment in full in
cash or Cash Equivalents of all Guarantor Senior Debt, the Holders of Guarantee
Obligations of any Guarantor shall be subrogated to the rights of the holders of
Guarantor Senior Debt of such Guarantor to receive payments or distributions of
cash, property or securities of such Guarantor applicable to such Guarantor
Senior Debt until all amounts owing on or in respect of the Guarantee
Obligations shall be paid in full; and, for the purposes of such subrogation, no
such payments or distributions to the holders of such Guarantor Senior Debt by
or on behalf of such Guarantor, or by or on behalf of the Holders by virtue of
this Article Twelve, which otherwise would have been made to the Holders shall,
as between such Guarantor and the Holders, be deemed to be a payment by such
Guarantor to or on account of such Guarantor Senior Debt, it being understood
that the provisions of this Article Twelve are and are intended solely for the
purpose of defining the relative rights of the Holders, on the one hand, and the
holders of Guarantor Senior Debt, on the other hand.

                                      -89-
<PAGE>   94

         Section 12.6 Obligations of the Guarantors Unconditional. Nothing
contained in this Article Twelve or elsewhere in this Indenture or in the
Guarantees is intended to or shall impair, as among the Guarantors, their
creditors other than the holders of Guarantor Senior Debt, and the Holders, the
obligation of the Guarantors, which is absolute and unconditional, to pay to the
Holders all amounts due and payable under the Guarantees as and when the same
shall become due and payable in accordance with their terms, or is intended to
or shall affect the relative rights of the Holders and creditors of the
Guarantors other than the holders of the Guarantor Senior Debt, nor shall
anything herein or therein prevent any Holder or the Trustee on its behalf from
exercising all remedies otherwise permitted by applicable law upon default under
this Indenture, subject to the rights, if any, in respect of cash, property or
securities of the Guarantors received upon the exercise of any such remedy.

         Section 12.7 Notice to Trustee. Each Guarantor shall give prompt
written notice to the Trustee of any fact known to such Guarantor which would
prohibit the making of any payment to or by the Trustee in respect of the
Guarantees pursuant to the provisions of this Article Twelve, although any delay
or failure to give any such notice shall have no effect on the subordination
provisions contained herein. Regardless of anything to the contrary contained in
this Article Twelve or elsewhere in this Indenture, the Trustee shall not be
charged with knowledge of the existence of any default or event of default with
respect to any Guarantor Senior Debt or of any other facts which would prohibit
the making of any payment to or by the Trustee unless and until the Trustee
shall have received notice in writing from a Guarantor, or from a holder of
Guarantor Senior Debt or a Representative therefor and, prior to the receipt of
any such written notice, the Trustee shall be entitled to assume (in the absence
of actual knowledge to the contrary) that no such facts exist. The Trustee shall
be entitled to rely on the delivery to it of any notice pursuant to this Section
12.7 to establish that such notice has been given by a holder of Senior Debt (or
a trustee thereof).

         In the event that the Trustee determines in good faith that any
evidence is required with respect to the right of any Person as a holder of
Guarantor Senior Debt to participate in any payment or distribution pursuant to
this Article Twelve, the Trustee may request such Person to furnish evidence to
the reasonable satisfaction of the Trustee as to the amounts of Guarantor Senior
Debt held by such Person, the extent to which such Person is entitled to
participate in such payment or distribution and any other facts pertinent to the
rights of such Person under this Article Twelve, and if such evidence is not
furnished the Trustee may defer any payment to such Person pending judicial
determination as to the right of such Person to receive such payment.

         Section 12.8 Reliance on Judicial Order or Certificate of Liquidating
Agent. Upon any payment or distribution of assets of a Guarantor referred to in
this Article Twelve, the Trustee, subject to the provisions of Article Seven
hereof, and the Holders shall be entitled to rely upon any order or decree made
by any court of competent jurisdiction in which any insolvency, bankruptcy,
receivership, dissolution, winding-up, liquidation, reorganization or similar
case or proceeding is pending, or upon a certificate of the trustee in
bankruptcy, liquidating trustee, receiver, assignee for the benefit of
creditors, agent or other person making such payment or distribution, delivered
to the Trustee or the Holders, for the purpose of ascertaining the persons
entitled to participate in such payment or distribution, the holders of the
Guarantor Senior Debt

                                      -90-
<PAGE>   95

and other Indebtedness of such Guarantor, the amount thereof or payable thereon,
the amount or amounts paid or distributed thereon and all other facts pertinent
thereto or to this Article Twelve.

         Section 12.9 Trustee's Relation to Guarantor Senior Debt. The Trustee
and any agent of a Guarantor or the Trustee shall be entitled to all the rights
set forth in this Article Twelve with respect to any Guarantor Senior Debt which
may at any time be held by it in its individual or any other capacity to the
same extent as any other holder of Guarantor Senior Debt and nothing in this
Indenture shall deprive the Trustee or any such agent of any of its rights as
such holder.

         With respect to the holders of Guarantor Senior Debt, the Trustee
undertakes to perform or to observe only such of its covenants and obligations
as are specifically set forth in this Article Twelve, and no implied covenants
or obligations with respect to the holders of Guarantor Senior Debt shall be
read into this Indenture against the Trustee. The Trustee shall not be deemed to
owe any fiduciary duty to the holders of Guarantor Senior Debt.

         Whenever a distribution is to be made or a notice given to holders or
owners of Guarantor Senior Debt, the distribution may be made and the notice may
be given to their Representative, if any.

         Section 12.10 Subordination Rights Not Impaired by Acts or Omissions of
the Guarantors or Holders of Guarantor Senior Debt. No right of any present or
future holders of any Guarantor Senior Debt to enforce subordination as provided
herein shall at any time in any way be prejudiced or impaired by any act or
failure to act on the part of any Guarantor or by any act or failure to act, in
good faith, by any such holder, or by any noncompliance by any Guarantor with
the terms of this Indenture, regardless of any knowledge thereof which any such
holder may have or otherwise be charged with.

         Without in any way limiting the generality of the foregoing paragraph,
the holders of Guarantor Senior Debt may, at any time and from time to time,
without the consent of or notice to the Trustee, without incurring
responsibility to the Trustee or the Holders of the Securities and without
impairing or releasing the subordination provided in this Article Twelve or the
obligations hereunder of the Holders of the Securities to the holders of
Guarantor Senior Debt, do any one or more of the following: (i) change the
manner, place or terms of payment or extend the time of payment of, or renew or
alter, Guarantor Senior Debt, or otherwise amend or supplement in any manner
Guarantor Senior Debt, or any instrument evidencing the same or any agreement
under which Guarantor Senior Debt is outstanding; (ii) sell, exchange, release
or otherwise deal with any property pledged, mortgaged or otherwise securing
Guarantor Senior Debt; (iii) release any Person liable in any manner for the
payment or collection of Guarantor Senior Debt; and (iv) exercise or refrain
from exercising any rights against the Guarantors and any other Person.

         Section 12.11 Holders Authorize Trustee To Effectuate Subordination of
Guarantee Obligations. Each Holder of Guarantee Obligations by its acceptance
thereof authorizes and expressly directs the Trustee on its behalf to take such
action as may be necessary or appropriate to effectuate, as between the holders
of Guarantor Senior Debt and the Holders, the subordination provided in this
Article Twelve, and appoints the Trustee its attorney-in-fact for such purposes,

                                      -91-
<PAGE>   96

including, in the event of any dissolution, winding-up, liquidation or
reorganization of any Guarantor (whether in bankruptcy, insolvency,
receivership, reorganization or similar proceedings or upon an assignment for
the benefit of credits or otherwise) tending towards liquidation of the business
and assets of any Guarantor, the filing of a claim for the unpaid balance under
its Guarantee Obligations and accrued interest in the form required in those
proceedings.

         If the Trustee does not file a proper claim or proof of debt in the
form required in such proceeding prior to 30 days before the expiration of the
time to file such claim or claims, then the holders of the Guarantor Senior Debt
or their Representative are or is hereby authorized to have the right to file
and are or is hereby authorized to file an appropriate claim for and on behalf
of the Holders of said Guarantee Obligations. Nothing herein contained shall be
deemed to authorize the Trustee or any holder of Guarantor Senior Debt or its
Representative to authorize or consent to or accept or adopt on behalf of any
Holder any plan of reorganization, arrangement, adjustment or composition
affecting the Guarantee Obligations or the rights of any Holder thereof, or to
authorize the Trustee or the holders of Guarantor Senior Debt or their
Representative to vote in respect of the claim of any Holder in any such
proceeding.

         Section 12.12 This Article Twelve Not To Prevent Events of Default. The
failure to make a payment on account of principal of or interest on the
Guarantees by reason of any provision of this Article Twelve will not be
construed as preventing the occurrence of an Event of Default.

         Section 12.13 Trustee's Compensation Not Prejudiced. Nothing in this
Article Twelve will apply to amounts due to the Trustee pursuant to other
sections of this Indenture.

                                ARTICLE THIRTEEN

                                  MISCELLANEOUS

         Section 13.1 TIA Controls. If any provision of this Indenture limits,
qualifies, or conflicts with another provision which is required or deemed to be
included in this Indenture by the TIA, such required or deemed provision shall
control.

         Section 13.2 Notices. Any notices or other communications required or
permitted hereunder shall be in writing, and shall be sufficiently given if made
by hand delivery, by telex, by telecopier or registered or certified mail,
postage prepaid, return receipt requested, addressed as follows:

         if to the Issuers or a Guarantor:
           c/o Orius Corp.
           1401 Forum Way, Suite 400
           West Palm Beach, FL  33401
           Attention:  Robert E. Agres

                                      -92-
<PAGE>   97

           Telephone:  561-687-8300
           Facsimile:  561-687-8080

         with a copy to:

           Kirkland & Ellis
           200 E. Randolph Drive, 54th Floor
           Chicago, IL  60601-6636
           Attention:  Dennis M. Meyers

           Telephone:  312-861-2000
           Facsimile:  312-861-2200

         if to the Trustee:

           United States Trust Company of New York
           114 West 47th Street
           New York, New York 10036-1532
           Attention:  Corporate Trust Administration

           Telephone:  212-852-1662
           Facsimile:  212-852-1626

         with a copy to:

           Winston & Strawn
           200 Park Avenue, 42nd Floor
           New York, New York 10166-4193
           Attention: Jeffrey H. Elkin, Esq.

           Telephone: 212-294-6711
           Facsimile: 212-294-4700

         Each of the Issuers and the Trustee by written notice to each other
such Person may designate additional or different addresses for notices to such
Person. Any notice or communication to the Issuers and the Trustee, shall be
deemed to have been given or made as of the date so delivered if personally
delivered; when answered back, if telexed; when receipt is acknowledged, if
telecopied; and five (5) calendar days after mailing if sent by registered or
certified mail, postage prepaid (except that any notice or communication to the
Trustee or a notice of change of address shall not be deemed to have been given
until actually received by the addressee).

         Any notice or communication mailed to a Securityholder shall be mailed
to him by first class mail or other equivalent means at his address as it
appears on the registration books of the Registrar and shall be sufficiently
given to him if so mailed within the time prescribed.

                                      -93-
<PAGE>   98

         Failure to mail a notice or communication to a Securityholder or any
defect in it shall not affect its sufficiency with respect to other
Securityholders. If a notice or communication is mailed in the manner provided
above, it is duly given, whether or not the addressee receives it.

         Section 13.3 Communications by Holders with Other Holders.
Securityholders may communicate pursuant to TIA ss. 312(b) with other
Securityholders with respect to their rights under this Indenture, the
Securities or the Guarantees. The Issuers, the Trustee, the Registrar and any
other Person shall have the protection of TIA ss. 312(c).

         Section 13.4 Certificate and Opinion as to Conditions Precedent. Upon
any request or application by the Issuers to the Trustee to take any action
under this Indenture, each Issuer shall furnish to the Trustee at the request of
the Trustee:

         (1) an Officers' Certificate, in form and substance satisfactory to the
Trustee, stating that, in the opinion of the signers, all conditions precedent
to be performed or effected by the Issuers, if any, provided for in this
Indenture relating to the proposed action have been complied with; and

         (2) an Opinion of Counsel stating that, in the opinion of such counsel,
any and all such conditions precedent have been complied with.

         Section 13.5 Officers' Certificates and Opinions of Counsel. (a) Each
Officers' Certificate or Opinion of Counsel with respect to compliance with a
condition or covenant provided for in this Indenture, other than the Officers'
Certificate required by Section 4.8 (which shall contain the statements set
forth therein), shall include:

         (1) a statement that the Person making such certificate or opinion has
read such covenant or condition;

         (2) a brief statement as to the nature and scope of the examination or
investigation upon which the statements or opinions contained in such
certificate or opinion are based;

         (3) a statement that, in the opinion of such Person, he has made such
examination or investigation as is necessary to enable him to express an
informed opinion as to whether or not such covenant or condition has been
complied with; and

         (4) a statement as to whether or not, in the opinion of each such
Person, such condition or covenant has been complied with; provided, that with
respect to matters of fact an Opinion of Counsel may rely on an Officers'
Certificate or certificates of public officials.

         (b) In the event that Officers' Certificates or Opinions of Counsel are
required to be delivered by more than one Person, such Persons may jointly
deliver a single Officers' Certificate or Opinion of Counsel as applicable,
provided, that in the case of an Officers' Certificate, such Officers'
Certificate is signed by two Officers of each Person required to deliver such
Officers' Certificate.

                                      -94-
<PAGE>   99

         Section 13.6 Rules by Trustee, Paying Agent, Registrar. The Trustee,
Paying Agent or Registrar may make reasonable rules for its functions.

         Section 13.7 Legal Holidays. If a payment date is not a Business Day,
payment may be made on the next succeeding day that is a Business Day.

         Section 13.8 Governing Law. THIS INDENTURE, THE SECURITIES AND THE
GUARANTEES WILL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
STATE OF NEW YORK, AS APPLIED TO CONTRACTS MADE AND PERFORMED WITHIN THE STATE
OF NEW YORK, WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAW. Each of the
parties hereto agrees to submit to the jurisdiction of the courts of the State
of New York in any action or proceeding arising out of or relating to this
Indenture, the Securities or the Guarantees.

         Section 13.9 No Adverse Interpretation of Other Agreements. This
Indenture may not be used to interpret another indenture, loan or debt agreement
of any of Parent, the Issuers or any of their Subsidiaries. Any such indenture,
loan or debt agreement may not be used to interpret this Indenture.

         Section 13.10 No Recourse Against Others. A director, officer,
employee, member, stockholder or incorporator, as such, of Parent or any of its
Subsidiaries shall not have any liability for any obligations of the Issuers in
respect of the Securities or for any claim based on, in respect of or by reason
of such obligations or their creation; provided, that the foregoing shall in no
way limit the obligations of any Guarantor in respect of the Guarantees. Each
Securityholder by accepting a Security waives and releases all such liability.
Such waiver and release are part of the consideration for the issuance of the
Securities.

         Section 13.11 Successors. All agreements of the Issuers and the
Guarantors in this Indenture, the Securities and the Guarantees shall bind their
respective successors. All agreements of the Trustee in this Indenture shall
bind its successor.

         Section 13.12 Duplicate Originals. All parties may sign any number of
copies of this Indenture. Each signed copy or counterpart shall be an original,
but all of them together shall represent the same agreement.

         Section 13.13 Severability. In case any one or more of the provisions
in this Indenture, in the Securities or in the Guarantees shall be held invalid,
illegal or unenforceable, in any respect for any reason, the validity, legality
and enforceability of any such provision in every other respect and of the
remaining provisions shall not in any way be affected or impaired thereby, it
being intended that all of the provisions hereof shall be enforceable to the
full extent permitted by law.

         Section 13.14 References to Parent's Board of Directors. In the event
that Parent should cease to own and control a majority of the Voting Securities
of NATG, all references herein to Parent's Board of Directors shall thenceforth
be deemed to be references to NATG's Board of Directors.

                                      -95-
<PAGE>   100

                  IN WITNESS WHEREOF, the parties hereto have caused this
Indenture to be duly executed all as of the date first written above.

                              NATG HOLDINGS, LLC

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Chief Executive Officer and
                                        President

                              ORIUS CAPITAL CORP.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: President

                              GUARANTORS:

                              ORIUS CORP.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Chief Executive Officer and
                                        President

                               NORTH AMERICAN TEL-COM
                               GROUP, INC.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Chief Executive Officer and
                                        President

                               LISN COMPANY,

                               By /s/ Robert C. Froetscher
                                 -----------------------------------------------
                                 Name: Robert C. Froetscher
                                 Title: Assistant Secretary

                                      -96-

<PAGE>   101

                              LISN, INC.,

                              By /s/ Robert C. Froetscher
                                 -----------------------------------------------
                                 Name: Robert C. Froetscher
                                 Title: Assistant Secretary

                              ARION SUB, INC.

                              By /s/ Robert C. Froetscher
                                 -----------------------------------------------
                                 Name: Robert C. Froetscher
                                 Title: Assistant Secretary

                              CATV SUBSCRIBER SERVICES, INC.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                              CABLEMASTERS, CORP.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                              CHANNEL COMMUNICATIONS, INC.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                              EXCEL CABLE CONSTRUCTION, INC.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                                      -97-

<PAGE>   102

                              MICH-COM CABLE SERVICES
                              INCORPORATED

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                              STATE WIDE CATV, INC.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                              U.S. CABLE, INC.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                              DAS-CO OF IDAHO, INC.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                              NETWORK CABLING SERVICES, INC.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                              SCHATZ UNDERGROUND CABLE,
                              INC.

                              By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                                     -98-

<PAGE>   103

                               COPENHAGEN UTILITIES &
                               CONSTRUCTION INC.

                               By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                               TEXEL CORPORATION

                               By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                               IRWIN TELECOMSERVICES, L.P., F/K/A
                               IRWIN ACQUISITION, L.P.

                               By: SCHATZ UNDERGROUND CABLE,
                               INC., its general partner

                               By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                               IRWIN TELECOM HOLDINGS, INC.

                               By /s/ William J. Mercurio
                                 -----------------------------------------------
                                 Name: William J. Mercurio
                                 Title: Executive Vice President

                               UNITED STATES TRUST COMPANY OF
                                 NEW YORK, as Trustee

                               By /s/ Gerard F. Ganey
                                 -----------------------------------------------
                                 Name: Gerard F. Ganey
                                 Title: Senior Vice President

                                      -99-

<PAGE>   104

                                                                      EXHIBIT A

                               NATG HOLDINGS, LLC
                               ORIUS CAPITAL CORP.
                   12 3/4% Senior Subordinated Notes due 2010

                                              CUSIP No.       [144A: 62874L AA4]
                                                            [Reg. S: U62918 AA2]
                                                                [AI: 62874L AB2]

No.                      $

         NATG HOLDINGS, LLC, a Delaware limited liability company, and ORIUS
CAPITAL CORP., a Delaware corporation (together the "Issuers", which term
includes any successors), for value received jointly and severally promise to
pay to CEDE & CO. or registered assigns, the principal sum of
$_________________on _______ ___, 2010.

         Interest Payment Dates:  August 1 and February 1, commencing August 1,
         2000.

         Record Dates:  July 15 and January 15.

         Reference is made to the further provisions of this Security set forth
on the reverse hereof, which will for all purposes have the same effect as if
set forth at this place.

<PAGE>   105

                                                                       EXHIBIT A
                                                                          Page 2

          IN WITNESS WHEREOF, the Issuers have caused this Security to be signed
manually or by facsimile by its duly authorized officers.

         Dated:  February ___, 2000

                                   NATG HOLDINGS, LLC

                                   By_____________________________
                                      Name:
                                      Title:

                                   By_____________________________
                                      Name:
                                      Title:

                                   ORIUS CAPITAL CORP.

                                   By_____________________________
                                      Name:
                                      Title:

                                   By_____________________________
                                      Name:
                                      Title:

                [FORM OF TRUSTEE'S CERTIFICATE OF AUTHENTICATION]

         This is one of the 12 3/4% Senior Subordinated Notes due 2010 described
in the within-mentioned Indenture.

         Dated:  February ___, 2000

                                   UNITED STATES TRUST COMPANY OF
                                     NEW YORK, as Trustee

                                   By:_____________________________
                                      Authorized Signatory

<PAGE>   106

                                                                       EXHIBIT A
                                                                          Page 3

                              (REVERSE OF SECURITY)

                                NATG HOLDINS, LLC
                               ORIUS CAPITAL CORP.

                        12 3/4% Senior Subordinated Note

                              due February 1, 2010

         1.   Interest.

         The Issuers jointly and severally promise to pay interest on the
principal amount of this Security at the rate per annum shown above. The Issuers
will pay interest semi-annually on August 1 and February 1 of each year (each,
an "Interest Payment Date"), commencing August 1, 2000. Interest on this
Security will accrue from the most recent date to which interest has been paid
or, if no interest has been paid, from February 9, 2000. Interest on this
Security will be computed on the basis of a 360-day year of twelve 30-day
months.

         The Issuers shall pay interest on overdue principal from time to time
on demand at the rate borne by this Security plus 1.5% and on overdue
installments of interest (without regard to any applicable grace periods) to the
extent lawful.

         2.   Method of Payment.

         The Issuers shall pay interest on the Securities (except defaulted
interest) to the persons who are the registered Holders at the close of business
on the Record Date immediately preceding the Interest Payment Date even if the
Securities are cancelled on registration of transfer or registration of exchange
after such Record Date. Holders must surrender Securities to a Paying Agent to
collect principal payments. The Issuers shall pay principal and interest in
money of the United States that at the time of payment is legal tender for
payment of public and private debts ("U.S. Legal Tender"). However, the Issuers
may pay principal and interest by wire transfer of Federal funds, or interest by
check payable in such U.S. Legal Tender. The Issuers may deliver any such
interest payment to the Paying Agent or to a Holder at the Holder's registered
address.

         3.  Paying Agent and Registrar.

         Initially, the United States Trust Company of New York (the "Trustee")
will act as Paying Agent and Registrar. The Issuers may change any Paying Agent,
Registrar or co-Registrar without notice to the Holders. The Issuers or any of
its Subsidiaries may, subject to certain exceptions, act as Registrar or
co-Registrar.

         4.   Indenture.

         The Issuers issued the Securities under an Indenture, dated as of
February 9, 2000 (the "Indenture"), among the Issuers, Parent and the other
Guarantors named therein and the Trustee.

<PAGE>   107

                                                                       EXHIBIT A
                                                                          Page 4

This Security is one of a duly authorized issue of Securities of the Issuers
designated as their 12 3/4% Senior Subordinated Notes due 2010 (the
"Securities"). The Securities are treated as a single class of securities under
the Indenture unless otherwise specified in the Indenture. Capitalized terms
herein are used as defined in the Indenture unless otherwise defined herein. The
terms of the Securities include those stated in the Indenture and those made
part of this Indenture by reference to the Trust Indenture Act of 1939 (15
U.S.C. ss.ss. 77aaa-77bbbb) (the "TIA"), as in effect on the Issue Date until
such time as the Indenture is qualified under the TIA, and thereafter as in
effect on the date on which this Indenture is qualified under the TIA.
Notwithstanding anything to the contrary herein, the Securities are subject to
all such terms, and Holders of Securities are referred to the Indenture and the
TIA for a statement of them. The Securities are general obligations of the
Issuers limited in aggregate principal amount to $300.0 million.

         5.   Subordination.

         The Securities are subordinated in right of payment, in the manner and
to the extent set forth in the Indenture, to the prior payment in full in cash
or Cash Equivalents of all Senior Debt of the Issuers, whether outstanding on
the date of the Indenture or thereafter created, incurred, assumed or
guaranteed. Each Holder by his acceptance hereof agrees to be bound by such
provisions and authorizes and expressly directs the Trustee, on his behalf, to
take such action as may be necessary or appropriate to effectuate the
subordination provided for in the Indenture and appoints the Trustee his
attorney-in-fact for such purposes.

         6.   Optional Redemption.

         The Securities will be redeemable, at the Issuers' option, in whole at
any time or in part from time to time, on and after February 1, 2005, upon not
less than 30 nor more than 60 days' notice, at the following Redemption Prices
(expressed as percentages of the principal amount) if redeemed during the
twelve-month period commencing on February 1 of the years set forth below, plus,
in each case, accrued and unpaid interest thereon, if any, to the date of
redemption:

<TABLE>
<CAPTION>

                    Year                                                         Percentage
                    ----                                                         ----------
<S>                                                                               <C>
2005..................................                                            106.375%
2006..................................                                            104.250%
2007..................................                                            102.125%
2008..................................                                            100.000%
</TABLE>

<PAGE>   108

                                                                       EXHIBIT A
                                                                          Page 5
         7.  Optional Redemption upon Equity Offerings.

         At any time, or from time to time, on or prior to February 1, 2003, the
Issuers may, at their option, use the net cash proceeds of one or more Equity
Offerings to redeem up to 35% aggregate principal amount of the Securities
issued pursuant to the Indenture at a Redemption Price equal to 112.750% of the
principal amount thereof, plus accrued and unpaid interest thereon, if any, to
the date of redemption; provided, that after any such redemption the aggregate
principal amount of Securities outstanding must equal at least 65% of the
aggregate principal amount of the Securities issued pursuant to the Indenture.
In order to effect the foregoing redemption with the net cash proceeds of any
Equity Offering, the Issuers shall make such redemption not more than 60 days
after the consummation of any such Equity Offering.

         8.   Notice of Redemption.

         Notice of redemption will be mailed at least 30 days but not more than
60 days before the Redemption Date to each Holder of Securities to be redeemed
at such Holder's registered address. Securities in denominations of $1,000 may
be redeemed only in whole. The Trustee may select for redemption portions (equal
to $1,000 or any integral multiple thereof) of the principal of Securities that
have denominations larger than $1,000.

         If any Security is to be redeemed in part only, the notice of
redemption that relates to such Security shall state the portion of the
principal amount thereof to be redeemed. A new Security in a principal amount
equal to the unredeemed portion thereof will be issued in the name of the Holder
thereof upon cancellation of the original Security. On and after the Redemption
Date, interest will cease to accrue on Securities or portions thereof called for
redemption.

         9.   Change of Control Offer.

         Upon the occurrence of a Change of Control, the Issuers will be
required to offer to purchase all of the outstanding Securities at a purchase
price equal to 101% of the principal amount thereof, plus accrued and unpaid
interest, if any, thereon to the date of repurchase.

         10.  Limitation on Asset Sales.

         The Issuers are, subject to certain conditions, obligated to make an
offer to purchase Securities at 100% of their principal amount, plus accrued and
unpaid interest, if any, thereon to the date of repurchase with certain cash
proceeds of certain sales or other dispositions of assets in accordance with the
Indenture.

         11.  Denominations; Transfer; Exchange.

         The Securities are in registered form, without coupons, in
denominations of $1,000 and integral multiples of $1,000. A Holder shall
register the transfer of or exchange Securities in accordance with the
Indenture. The Registrar may require a Holder, among other things, to furnish
appropriate endorsements and transfer documents and to pay certain transfer
taxes or similar governmental charges payable in connection therewith as
permitted by the Indenture.

<PAGE>   109
                                                                       EXHIBIT A
                                                                          Page 6

The Registrar need not register the transfer of or exchange any Securities or
portions thereof selected for redemption, except the unredeemed portion of any
security being redeemed in part.

         12.  Persons Deemed Owners.

         The registered Holder of a Security shall be treated as the owner
thereof for all purposes.

         13.  Unclaimed Funds.

         If funds for the payment of principal or interest remain unclaimed for
two years, the Trustee and the Paying Agent will, subject to certain
requirements, repay the funds to the Issuers at their request. After that, all
liability of the Trustee and such Paying Agent with respect to such funds shall
cease.

         14.  Discharge Prior to Redemption or Maturity.

         The Issuers and the Guarantors may be discharged from their obligations
under the Indenture, the Securities and the Guarantees except for certain
provisions thereof, and may be discharged from obligations to comply with
certain covenants contained in the Indenture, the Securities and the Guarantees,
in each case upon satisfaction of certain conditions specified in the Indenture.

         15.  Amendment; Supplement; Waiver.

         Subject to certain exceptions, the Indenture, the Securities and the
Guarantees may be amended or supplemented with the written consent of the
Holders of at least a majority in aggregate principal amount of the Securities
then outstanding, and any existing Default or Event of Default or compliance
with any provision may be waived with the consent of the Holders of a majority
in aggregate principal amount of the Securities then outstanding. Without notice
to or consent of any Holder, the parties thereto may amend or supplement the
Indenture, the Securities and the Guarantees to, among other things, cure any
ambiguity, defect or inconsistency, provide for uncertificated Securities in
addition to or in place of certificated Securities or comply with any
requirements of the Commission in connection with the qualification of the
Indenture under the TIA, or make any other change that does not materially
adversely affect the rights of any Holder of a Security.

         16.  Restrictive Covenants.

         The Indenture contains certain covenants that, among other things,
limit the ability of the NATG and its Restricted Subsidiaries to make Restricted
Payments, to incur Indebtedness, to create Liens, to sell assets, to permit
restrictions on dividends and other payments by Restricted Subsidiaries of the
Issuers to the Issuers, to consolidate, merge or sell all or substantially all
of their assets or to engage in transactions with affiliates. The limitations
are subject to a number of important qualifications and exceptions. The Issuers
must annually report to the Trustee on compliance with such limitations.

<PAGE>   110
                                                                       EXHIBIT A
                                                                          Page 7

         17.  Defaults and Remedies.

         If an Event of Default occurs and is continuing, the Trustee or the
Holders of at least 25% in aggregate principal amount of Securities then
outstanding may declare all the Securities to be due and payable immediately in
the manner and with the effect provided in the Indenture. Holders of Securities
may not enforce the Indenture, the Securities or the Guarantees except as
provided in the Indenture. The Trustee is not obligated to enforce the
Indenture, the Securities or the Guarantees unless it has received indemnity
satisfactory to it. The Indenture permits, subject to certain limitations
therein provided, Holders of a majority in aggregate principal amount of the
Securities then outstanding to direct the Trustee in its exercise of any trust
or power. The Trustee may withhold from Holders of Securities notice of certain
continuing Defaults or Events of Default if it determines that withholding
notice is in their interest.

         18.  Trustee Dealings with Company.

         The Trustee under the Indenture, in its individual or any other
capacity, may become the owner or pledgee of Securities and may otherwise deal
with Parent, the Issuers, their subsidiaries and their respective Affiliates as
if it were not the Trustee.

         19.  No Recourse Against Others.

         No stockholder, director, officer, member, employee or incorporator, as
such, of Parent, the Issuers or any of their subsidiaries shall have any
liability for any obligation of the Issuers in respect of the Securities or for
any claim based on, in respect of or by reason of, such obligations or their
creation; provided, that the foregoing shall in no way limit the obligations of
any Guarantor in respect of its Guarantee. Each Holder of a Security by
accepting a Security waives and releases all such liability. The waiver and
release are part of the consideration for the issuance of the Securities.

         20.  Authentication.

         This Security shall not be valid until the Trustee or authenticating
agent signs the certificate of authentication on this Security.

         21.  Abbreviations and Defined Terms.

         Customary abbreviations may be used in the name of a Holder of a
Security or an assignee, such as: TEN COM (= tenants in common), TEN ENT (=
tenants by the entireties), JT TEN (= joint tenants with right of survivorship
and not as tenants in common), CUST (= Custodian), and U/G/M/A (= Uniform Gifts
to Minors Act).

         22.  Governing Law.

         This Security shall be governed by, and construed in accordance with,
the laws of the State of New York, as applied to contracts made and performed
within the State of New York, without regard to applicable principles of
conflicts of laws.

<PAGE>   111

                                                                       EXHIBIT A
                                                                          Page 8

         23.  CUSIP Numbers.

         Pursuant to a recommendation promulgated by the Committee on Uniform
Security Identification Procedures, the Issuers have caused CUSIP numbers to be
printed on the Securities as a convenience to the Holders of the Securities. No
representation is made as to the accuracy of such numbers as printed on the
Securities and reliance may be placed only on the other identification numbers
printed hereon.

         24.  Registration Rights.(1)

         Pursuant to, but subject to the exceptions in, the Registration Rights
Agreement, the Issuers and the Guarantors will be obligated to consummate an
exchange offer pursuant to which the Holder of this Security shall have the
right to exchange this Security for a 12 3/4% Senior Subordinated Note due 2010
of the Issuers which shall have been registered under the Securities Act, in
like principal amount and having terms identical in all material respects as
this Security. The Holders shall be entitled to receive certain additional
interest payments in the event such exchange offer is not consummated or the
Securities are not offered for resale and upon certain other conditions, all
pursuant to and in accordance with the terms of the Registration Rights
Agreement.

         25.  Indenture.

         Each Holder, by accepting a Security, agrees to be bound by all of the
terms and provisions of the Indenture, as the same may be amended from time to
time. Capitalized terms used herein and not defined herein have the meanings
ascribed thereto in the Indenture.

         26.  Guarantees.

         This Security will be entitled to the benefits of certain senior
subordinated Guarantees made for the benefit of the Holders. Reference is hereby
made to the Indenture for a statement of the respective rights, limitations of
rights, duties and obligations thereunder of the Guarantors, the Trustee and the
Holders.

         The Issuers will furnish to any Holder of a Security upon written
request and without charge a copy of the Indenture. Requests may be made to:
NATG HOLDINGS, INC. and ORIUS CAPITAL CORP. at 1401 Forum Way, Suite 400, West
Palm Beach, FL 33401, Attention: Chief Financial Officer.

----------------
(1) Not applicable to Form of Exchange Securities
<PAGE>   112
                                                                       EXHIBIT A
                                                                          Page 9

                                 ASSIGNMENT FORM

 I or we assign and transfer this Security to

 _______________________________________________________________________________

 _______________________________________________________________________________
 (Print or type name, address and zip code of assignee or transferee)

 ______________________________________________________________________________
 (Insert Social Security or other identifying number of assignee or transferee)

 and irrevocably appoint _______________________________________ agent
to transfer this Security on the books of the Issuers. The agent may substitute
another to act for him.

         Dated: _________________    Signed:  __________________________________

                                             (Sign exactly as name appears on
                                             the other side of this Security)

         Signature Guarantee:      _____________________________________________

                                   Participant in a recognized Signature
                                   Guarantee Medallion Program (or other
                                   signature guarantor program reasonably
                                   acceptable to the Trustee)

<PAGE>   113
                                                                       EXHIBIT A
                                                                         Page 10

         In connection with any transfer of this Security occurring prior to the
date which is the earlier of (i) the date of the declaration by the Commission
of the effectiveness of a registration statement under the Securities Act of
1933, as amended (the "Securities Act") covering resales of this Security (which
effectiveness shall not have been suspended or terminated at the date of the
transfer) and (ii) February 9, 2002 the undersigned confirms that it has not
utilized any general solicitation or general advertising in connection with the
transfer:

                                   [Check One]

          (1)  ___ to Orius Corp., the Issuers or a subsidiary thereof; or

          (2)  ___ pursuant to and in compliance with Rule 144A under the
                   Securities Act of 1933, as amended; or

          (3)  ___ to an institutional "accredited investor" (as defined in Rule
                   501(a)(1), (2), (3) or (7) under the Securities Act of 1933,
                   as amended) that has furnished to the Trustee a signed letter
                   containing certain representations and agreements (the form
                   of which letter can be obtained from the Trustee); or

          (4)  ___ outside the United States to a "foreign purchaser" in
                   compliance with Rule 904 of Regulation S under the Securities
                   Act of 1933, as amended; or

          (5)  ___ pursuant to the exemption from registration provided by Rule
                   144 under the Securities Act of 1933, as amended; or

          (6)  ___ pursuant to an effective registration statement under the
                   Securities Act of 1933, as amended; or

          (7)  ___ pursuant to another available exemption from the registration
                   requirements of the Securities Act of 1933, as amended.

and unless the box below is checked, the undersigned confirms that such Security
is not being transferred to an "affiliate" of the Issuers as defined in Rule 144
under the Securities Act of 1933, as amended (an "Affiliate"):

          ___  The transferee is an Affiliate of the Issuers.

         Unless one of the items is checked, the Trustee will refuse to register
any of the Securities evidenced by this certificate in the name of any person
other than the registered Holder thereof; provided, that if item (3), (4), (5)
or (7) is checked, the Issuers or the Trustee may require, prior to registering
any such transfer of the Securities, in their sole discretion, such written
legal opinions, certifications (including an investment letter in the case of
box (3) or (4) and other information as the Trustee or the Issuers have
reasonably requested to confirm that such transfer is being made pursuant to an
exemption from, or in a transaction not subject to, the registration
requirements of the Securities Act of 1933, as amended.

<PAGE>   114

                                                                       EXHIBIT A
                                                                         Page 11

         If none of the foregoing items are checked, the Trustee or Registrar
shall not be obligated to register this Security in the name of any person other
than the Holder hereof unless and until the conditions to any such transfer of
registration set forth herein and in Section 2.16 of the Indenture shall have
been satisfied.

         Dated:_______________        Signed:___________________________________

                                      (Sign  exactly as name appears on the
                                      other side of this Security)
         Signature
         Guarantee:___________________________________________________

              TO BE COMPLETED BY PURCHASER IF (2) ABOVE IS CHECKED

         The undersigned represents and warrants that it is purchasing this
Security for its own account or an account with respect to which it exercises
sole investment discretion and that it and any such account is a "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act of
1933, as amended, and is aware that the sale to it is being made in reliance on
Rule 144A and acknowledges that it has received such information regarding the
Issuers as the undersigned has requested pursuant to Rule 144A or has determined
not to request such information and that it is aware that the transferor is
relying upon the undersigned's foregoing representations in order to claim the
exemption from registration provided by Rule 144A.

         Dated:_______________        __________________________________________

                                  NOTICE: To be executed by an executive officer

<PAGE>   115

                                                                       EXHIBIT A
                                                                         Page 12

                       OPTION OF HOLDER TO ELECT PURCHASE

     If you want to elect to have this Security purchased by the Issuers
pursuant to Section 4.15 or Section 4.16 of the Indenture, check the appropriate
box:

     Section 4.15 [ ] Section 4.16 [ ]

     If you want to elect to have only part of this Security purchased by the
Issuers pursuant to Section 4.15 or Section 4.16 of the Indenture, state the
amount: $___________

    Dated: _________________       Signed:  ____________________________

                                            (Sign exactly as name appears on the
                                            other  side of this Security)

    Signature Guarantee:   _______________________________________________

                           Participant in a recognized Signature Guarantee
                           Medallion Program (or other signature guarantor
                           program reasonably acceptable to the Trustee)

<PAGE>   116

                                                                       EXHIBIT B

                                 FORM OF LEGENDS

         Each Global Security and Physical Security that constitutes a
Restricted Security or is sold in compliance with Regulation S shall bear the
following legend (the "Private Placement Legend") on the face thereof until
after the second anniversary of its date of issuance, unless otherwise agreed by
the Issuer and the Holder thereof:

         THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE U.S. SECURITIES ACT OF
1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR
SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT OF, U.S.
PERSONS EXCEPT AS SET FORTH BELOW. BY ITS ACQUISITION HEREOF, THE HOLDER (1)
REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN RULE
144A UNDER THE SECURITIES ACT), (B) IT IS NOT A U.S. PERSON AND IS ACQUIRING
THIS SECURITY IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH RULE 904 UNDER THE
SECURITIES ACT OR (C) IT IS AN ACCREDITED INVESTOR (AS DEFINED IN RULE
501(a)(1), (2), (3), OR (7) UNDER THE SECURITIES ACT (AN "ACCREDITED INVESTOR"),
(2) AGREES THAT IT WILL NOT WITHIN TWO YEARS AFTER THE ORIGINAL ISSUANCE OF THIS
SECURITY RESELL OR OTHERWISE TRANSFER THIS SECURITY EXCEPT (A) TO ORIUS CORP.,
THE ISSUERS OR ANY SUBSIDIARY THEREOF, (B) INSIDE THE UNITED STATES TO A
QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES
ACT, (C) INSIDE THE UNITED STATES TO AN ACCREDITED INVESTOR THAT, PRIOR TO SUCH
TRANSFER, FURNISHES (OR HAS FURNISHED ON ITS BEHALF BY A U.S. BROKER-DEALER) TO
THE TRUSTEE A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS
RELATING TO THE RESTRICTIONS ON TRANSFER OF THIS SECURITY (THE FORM OF WHICH
LETTER CAN BE OBTAINED FROM THE TRUSTEE FOR THIS SECURITY), (D) OUTSIDE THE
UNITED STATES IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH REGULATION S UNDER
THE SECURITIES ACT (IF AVAILABLE), (E) PURSUANT TO THE EXEMPTION FROM
REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE), (F)
IN ACCORDANCE WITH ANOTHER EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE
SECURITIES ACT OR (G) PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE
SECURITIES ACT, AND (3) AGREES THAT IT WILL GIVE TO EACH PERSON TO WHOM THIS
SECURITY IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN
CONNECTION WITH ANY TRANSFER OF THIS SECURITY WITHIN TWO YEARS AFTER THE DATE OF
ORIGINAL ISSUANCE OF THIS SECURITY, IF THE PROPOSED TRANSFER IS BEING MADE TO AN
ACCREDITED INVESTOR, THE HOLDER MUST, PRIOR TO SUCH TRANSFER, FURNISH TO THE
TRUSTEE AND THE ISSUERS SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION
AS ANY OF THEM MAY REASONABLY REQUIRE TO CONFIRM THAT SUCH TRANSFER IS BEING
MADE PURSUANT TO AN EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT. AS USED HEREIN, THE TERMS
"OFFSHORE TRANSACTION," "UNITED STATES" AND

<PAGE>   117

                                                                       EXHIBIT B
                                                                          Page 2

"U.S. PERSON" HAVE THE MEANING GIVEN TO THEM BY REGULATION S UNDER THE
SECURITIES ACT.

         Each Global Security authenticated and delivered hereunder shall also
bear the following legend:

         THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE OF A DEPOSITARY OR A SUCCESSOR DEPOSITARY. THIS SECURITY IS NOT
EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A PERSON OTHER THAN THE
DEPOSITARY OR ITS NOMINEE EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE
INDENTURE, AND NO TRANSFER OF THIS SECURITY (OTHER THAN A TRANSFER OF THIS
SECURITY AS A WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A
NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE
DEPOSITARY) MAY BE REGISTERED EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN
THE INDENTURE.

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE ISSUERS OR
THEIR AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME
AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE
TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN. TRANSFERS OF THIS GLOBAL SECURITY
SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT NOT IN PART, TO NOMINEES OF CEDE &
CO. OR TO A SUCCESSOR THEREOF OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF
PORTIONS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS MADE IN
ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN SECTION 2.16 OF THE INDENTURE.

         Any Temporary Reg. S. Global Security shall bear the following legend:

         THIS SECURITY AND INTERESTS IN THIS SECURITY MAY NOT BE OFFERED OR SOLD
TO A U.S. PERSON (AS SUCH TERM IS DEFINED IN REGULATION S UNDER THE SECURITIES
ACT) OR FOR THE ACCOUNT OR BENEFIT OF A U.S. PERSON PRIOR TO THE EXPIRATION OF
THE DISTRIBUTION COMPLIANCE PERIOD (AS DEFINED IN THE INDENTURE), AND NO
TRANSFER OR EXCHANGE OF THIS SECURITY OR INTEREST IN THIS SECURITY MAY BE MADE
FOR A PHYSICAL SECURITY OR AN INTEREST IN A PHYSICAL SECURITY UNTIL AFTER THE
LATER OF THE DATE OF EXPIRATION OF THE DISTRIBUTION COMPLIANCE PERIOD AND

<PAGE>   118
                                                                       EXHIBIT B
                                                                          Page 3

THE DATE ON WHICH THE PROPER REQUIRED CERTIFICATION RELATING TO SUCH TRANSFER OR
EXCHANGE HAS BEEN PROVIDED IN ACCORDANCE WITH THE TERMS OF THE INDENTURE, TO THE
EFFECT THAT THE BENEFICIAL OWNER OR OWNERS OF SUCH INTEREST ARE NOT U.S.
PERSONS.

<PAGE>   119

                                                                       EXHIBIT C

                            Form of Certificate to Be
                          Delivered in Connection with
                    Transfers to Non-QIB Accredited Investors

                              [        ], [ ]

United States Trust Company of New York
114 West 47th Street
New York, New York 10036-1532
Attention: Corporate Trust Administration

Ladies and Gentlemen:

         In connection with our proposed purchase of 12 3/4% Senior Subordinated
Notes due 2010 (the "Securities") of NATG HOLDINGS, LLC, a Delaware limited
liability company, and ORIUS CAPITAL CORP., a Delaware corporation (together,
the "Issuers"), we confirm that:

         1. We have received a copy of the Offering Memorandum (the "Offering
Memorandum"), dated February 4, 2000, relating to the Securities and such other
information as we deem necessary in order to make our investment decision. We
acknowledge that we have read and agreed to the matters stated in the section
entitled "Transfer Restrictions" of such Offering Memorandum, including the
restrictions on duplication and circulation of the Offering Memorandum.

         2. We understand that any subsequent transfer of the Securities is
subject to certain restrictions and conditions set forth in the Indenture
relating to the Securities (the "Indenture") as described in the Offering
Memorandum and the undersigned agrees to be bound by, and not to resell, pledge
or otherwise transfer the Securities except in compliance with, such
restrictions and conditions and the Securities Act of 1933, as amended (the
"Securities Act"), and all applicable State securities laws.

         3. We understand that the offer and sale of the Securities have not
been registered under the Securities Act, and that the Securities may not be
offered or sold except as permitted in the following sentence. We agree, on our
own behalf and on behalf of any accounts for which we are acting as hereinafter
stated, that if we should sell any Securities, we will do so only (i) to Orius
Corp., the Issuers or any of their subsidiaries, (ii) inside the United States
in accordance with Rule 144A under the Securities Act to a "qualified
institutional buyer" (as defined in Rule 144A under the Securities Act), (iii)
inside the United States to an institutional "accredited investor" (as defined
below) that, prior to such transfer, furnishes (or has furnished on its behalf
by a U.S. broker-dealer) to the Trustee (as defined in the Indenture) a signed
letter containing certain representations and agreements relating to the
restrictions on transfer of the Securities (the form of which letter can be
obtained from the Trustee), (iv) outside the United States in accordance with
Rule 904 of Regulation S promulgated under the Securities Act to non-U.S.
persons, (v) pursuant to the exemption from registration provided by Rule 144
under the

<PAGE>   120

                                                                       EXHIBIT C
                                                                          Page 2

Securities Act (if available), or (vi) pursuant to an effective registration
statement under the Securities Act, and we further agree to provide to any
person purchasing any of the Securities from us a notice advising such purchaser
that resales of the Securities are restricted as stated herein.

         4. We are not acquiring the Securities for or on behalf of, and will
not transfer the Securities to, any pension or welfare plan (as defined in
Section 3 of the Employee Retirement Income Security Act of 1974), except as
permitted in the section entitled "Transfer Restrictions" of the Offering
Memorandum.

         5. We understand that, on any proposed resale of any Securities, we
will be required to furnish to the Trustee and the Issuers such certification,
legal opinions and other information as the Trustee and the Issuers may
reasonably require to confirm that the proposed sale complies with the foregoing
restrictions. We further understand that the Securities purchased by us will
bear a legend to the foregoing effect.

         6. We are an institutional "accredited investor" (as defined in Rule
501(a)(1), (2), (3) or (7) of Regulation D under the Securities Act) and have
such knowledge and experience in financial and business matters as to be capable
of evaluating the merits and risks of our investment in the Securities, and we
and any accounts for which we are acting are each able to bear the economic risk
of our or their investment, as the case may be.

         7. We are acquiring the Securities purchased by us for our account or
for one or more accounts (each of which is an institutional "accredited
investor") as to each of which we exercise sole investment discretion.

         You, the Issuers, the Trustee and others are entitled to rely upon this
letter and are irrevocably authorized to produce this letter or a copy hereof to
any interested party in any administrative or legal proceeding or official
inquiry with respect to the matters covered hereby.

                                            Very truly yours,

                                            [Name of Transferee]

                                            By__________________________________
                                                Name:
                                                Title:

<PAGE>   121

                                                                       EXHIBIT D

                       Form of Certificate To Be Delivered
                          in Connection with Transfers
                            Pursuant to Regulation S

                                 [      ], [ ]

United States Trust Company of New York
114 West 47th Street
New York, New York 10036-1532
Attention: Corporate Trust Administration

Ladies and Gentlemen:

         In connection with our proposed sale of [$ ] aggregate principal amount
of the 12 3/4% Senior Subordinated Notes due 2010 (the "Securities") of NATG
HOLDINGS, LLC, a Delaware limited liability company, and ORIUS CAPITAL CORP., a
Delaware corporation (together, the "Issuers"), we confirm that such sale has
been effected pursuant to and in accordance with Regulation S under the U.S.
Securities Act of 1933, as amended (the "Securities Act"), and, accordingly, we
represent that:

         (1) the offer of the Securities was not made to a person in the United
States;

         (2) either (a) at the time the buy offer was originated, the transferee
was outside the United States or we and any person acting on our behalf
reasonably believed that the transferee was outside the United States, or (b)
the transaction was executed in, on or through the facilities of a designated
off-shore securities market and neither we nor any person acting on our behalf
knows that the transaction has been pre-arranged with a buyer in the United
States;

         (3) no directed selling efforts have been made in the United States in
contravention of the requirements of Rule 903(b) or Rule 904(b) of Regulation S,
as applicable;

         (4) the transaction is not part of a plan or scheme to evade the
registration requirements of the Securities Act; and

         (5) we have advised the transferee of the transfer restrictions
applicable to the Securities.

<PAGE>   122
                                                                       EXHIBIT D
                                                                          Page 2

         You, the Issuers and counsel for the Issuers are entitled to rely upon
this letter and are irrevocably authorized to produce this letter or a copy
hereof to any interested party in any administrative or legal proceedings or
official inquiry with respect to the matters covered hereby. Terms used in this
certificate have the meanings set forth in Regulation S.

                                                     Very truly yours,

                                                     [Name of Transferor]

                                                     By:____________________
                                                          Authorized Signature
<PAGE>   123

                                                                       EXHIBIT E

                                    GUARANTEE

         For value received, each of the undersigned hereby unconditionally
guarantees, as principal obligor and not only as a surety, to the Holder of this
Security the cash payments in United States dollars of principal of, premium, if
any, and interest on this Security in the amounts and at the times when due and
interest on the overdue principal, premium, if any, and interest, if any, of
this Security, if lawful, and the payment or performance of all other
obligations of the Issuers under the Indenture (as defined below) or the
Securities, to the Holder of this Security and the Trustee, all in accordance
with and subject to the terms and limitations of this Security, Article Eleven
of the Indenture and this Guarantee. This Guarantee will become effective in
accordance with Article Eleven of the Indenture and its terms shall be evidenced
therein. The validity and enforceability of any Guarantee shall not be affected
by the fact that it is not affixed to any particular Security.

         Capitalized terms used but not defined herein shall have the meanings
ascribed to them in the Indenture dated as of February 9, 2000, among NATG
Holdings, LLC and Orius Capital Corp., as issuers (collectively, the "Issuers"),
the Guarantors named therein and the United States Trust Company of New York, as
trustee (the "Trustee"), as amended or supplemented (the "Indenture").

         The obligations of the undersigned to the Holders of Securities and to
the Trustee pursuant to this Guarantee and the Indenture are expressly set forth
in Article Eleven of the Indenture and reference is hereby made to the Indenture
for the precise terms of the Guarantee and all of the other provisions of the
Indenture to which this Guarantee relates.

         This Guarantee is subordinated in right of payment, in the manner and
to the extent set forth in Article Twelve of the Indenture, to the prior payment
in full in cash or Cash Equivalents of all Guarantor Senior Debt of the
Guarantors, whether outstanding on the date of the Indenture or thereafter
created, incurred, assumed or guaranteed.

         THIS GUARANTEE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH,
THE LAWS OF THE STATE OF NEW YORK AS APPLIED TO CONTRACTS MADE AND PERFORMED
WITHIN THE STATE OF NEW YORK, WITHOUT GIVING EFFECT TO PRINCIPLES OF CONFLICTS
OF LAW. Each undersigned Guarantor hereby agrees to submit to the jurisdiction
of the courts of the State of New York in any action or proceeding arising out
of or relating to this Guarantee.

         This Guarantee is subject to release upon the terms set forth in the
Indenture.

<PAGE>   124
                                                                       EXHIBIT E

         IN WITNESS WHEREOF, each Guarantor has caused its Guarantee to be duly
executed.

Date:  February ___, 2000

                                   ORIUS CORP.

                                   By_____________________________
                                      Name:
                                      Title:

                                   NORTH AMERICAN TEL-COM
                                   GROUP, INC.

                                   By_____________________________
                                      Name:
                                      Title:

                                   LISN COMPANY,

                                   By_____________________________
                                      Name:
                                      Title:

                                   LISN, INC.,

                                   By_____________________________
                                      Name:
                                      Title:

                                   ARION SUB, INC.

                                   By_____________________________
                                      Name:
                                      Title:

<PAGE>   125
                                                                       EXHIBIT E

                                   CATV SUBSCRIBER SERVICES, INC.

                                   By_____________________________
                                      Name:
                                      Title:

                                   CABLEMASTERS, CORP.

                                   By_____________________________
                                      Name:
                                      Title:

                                   CHANNEL COMMUNICATIONS, INC.

                                   By_____________________________
                                      Name:
                                      Title:

                                   EXCEL CABLE CONSTRUCTION, INC.

                                   By_____________________________
                                      Name:
                                      Title:

                                   MICH-COM CABLE SERVICES
                                   INCORPORATED

                                   By_____________________________
                                      Name:
                                      Title:

                                   STATE WIDE CATV, INC.

                                   By_____________________________
                                      Name:
                                      Title:

<PAGE>   126
                                                                       EXHIBIT E
                                   U.S. CABLE, INC.

                                   By_____________________________
                                      Name:
                                      Title:

                                   DAS-CO OF IDAHO, INC.

                                   By_____________________________
                                      Name:
                                      Title:

                                   NETWORK CABLING SERVICES, INC.

                                   By_____________________________
                                      Name:
                                      Title:

                                   SCHATZ UNDERGROUND CABLE,
                                   INC.

                                   By_____________________________
                                      Name:
                                      Title:

                                   COPENHAGEN UTILITIES &
                                   CONSTRUCTION INC.

                                   By_____________________________
                                      Name:
                                      Title:

                                   TEXEL CORPORATION

                                   By_____________________________
                                      Name:
                                      Title:

<PAGE>   127
                                                                       EXHIBIT E
                                   IRWIN ACQUISITION, L.P.

                                   By: SCHATZ UNDERGROUND CABLE,
                                   INC., its general partner

                                   By_____________________________
                                      Name:
                                      Title:

                                   IRWIN TELECOM HOLDINGS, INC.

                                   By_____________________________
                                      Name:
                                      Title:

<PAGE>   128

                                TABLE OF CONTENTS

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<S>            <C>                                                                                             <C>
ARTICLE ONE

DEFINITIONS AND INCORPORATION BY REFERENCE........................................................................1

   Section 1.1  Definitions.......................................................................................1
   Section 1.2  Incorporation by Reference of TIA................................................................27
   Section 1.3  Rules of Construction............................................................................27
   Section 1.4  Ancillary Agreements.............................................................................28

ARTICLE TWO

THE SECURITIES...................................................................................................28

   Section 2.1  Form and Dating..................................................................................28
   Section 2.2  Execution and Authentication.....................................................................29
   Section 2.3  Registrar and Paying Agent.......................................................................30
   Section 2.4  Paying Agent To Hold Assets in Trust.............................................................30
   Section 2.5  Holder Lists.....................................................................................31
   Section 2.6  Transfer and Exchange............................................................................31
   Section 2.7  Replacement Securities...........................................................................31
   Section 2.8  Outstanding Securities...........................................................................32
   Section 2.9  Treasury Securities..............................................................................32
   Section 2.10  Temporary Securities............................................................................32
   Section 2.11  Cancellation....................................................................................32
   Section 2.12  Defaulted Interest..............................................................................33
   Section 2.13  CUSIP Number....................................................................................33
   Section 2.14  Deposit of Moneys...............................................................................33
   Section 2.15  Book-Entry Provisions for Global Securities.....................................................33
   Section 2.16  Special Transfer Provisions.....................................................................34

ARTICLE THREE

REDEMPTION.......................................................................................................37

   Section 3.1  Notices to Trustee...............................................................................37
   Section 3.2  Selection of Securities To Be Redeemed...........................................................37
   Section 3.3  Notice of Redemption.............................................................................37
   Section 3.4  Effect of Notice of Redemption...................................................................38
   Section 3.5  Deposit of Redemption Price......................................................................38
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   Section 3.6  Securities Redeemed in Part......................................................................39
   Section 3.7  Optional Redemption..............................................................................39

ARTICLE FOUR

COVENANTS........................................................................................................39

   Section 4.1  Payment of Securities............................................................................39
   Section 4.2  Maintenance of Office or Agency..................................................................40
   Section 4.3  Limitation on Restricted Payments................................................................40
   Section 4.4  Limitation on Incurrence of Additional Indebtedness..............................................42
   Section 4.5  Corporate Existence..............................................................................42
   Section 4.6  Payment of Taxes and Other Claims................................................................43
   Section 4.7  Maintenance of Properties and Insurance..........................................................43
   Section 4.8  Compliance Certificate; Notice of Default........................................................43
   Section 4.9  Compliance with Laws.............................................................................44
   Section 4.10  Reports to Holders..............................................................................44
   Section 4.11  Waiver of Stay, Extension or Usury Laws.........................................................45
   Section 4.12  Limitations on Transactions with Affiliates.....................................................45
   Section 4.13  Limitation on Dividend and Other Payment Restrictions Affecting Restricted Subsidiaries.........46
   Section 4.14  Limitation on Liens.............................................................................47
   Section 4.15  Change of Control...............................................................................47
   Section 4.16  Limitation on Asset Sales.......................................................................49
   Section 4.17  Prohibition on Incurrence of Senior Subordinated Debt...........................................51
   Section 4.18  Additional Subsidiary Guarantees................................................................51

   Section 4.19  Conduct of Business.............................................................................52
   Section 4.20  Disposal of Subsidiary Stock....................................................................52
   Section 4.21  Payments for Consent............................................................................52
   Section 4.22  Maintenance of Separate Identity................................................................52

ARTICLE FIVE

SUCCESSOR CORPORATION............................................................................................53

   Section 5.1   Merger, Consolidation and Sale of Assets........................................................53
   Section 5.2   Success or Corporation Substituted..............................................................54

ARTICLE SIX

DEFAULT AND REMEDIES.............................................................................................54

   Section 6.1   Events of Default...............................................................................54
   Section 6.2   Acceleration....................................................................................56
</TABLE>

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<CAPTION>

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   Section 6.3  Other Remedies....................................................................................56
   Section 6.4  Waiver of Past Defaults...........................................................................56
   Section 6.5  Control by Majority...............................................................................57
   Section 6.6  Limitation on Suits...............................................................................57
   Section 6.7  Rights of Holders To Receive Payment..............................................................57
   Section 6.8  Collection Suit by Trustee........................................................................57
   Section 6.9  Trustee May File Proofs of Claim..................................................................58
   Section 6.10  Priorities.......................................................................................58
   Section 6.11  Undertaking for Costs............................................................................58

ARTICLE SEVEN

TRUSTEE...........................................................................................................59

   Section 7.1  Duties of Trustee.................................................................................59
   Section 7.2  Rights of Trustee.................................................................................60
   Section 7.3  Individual Rights of Trustee......................................................................61
   Section 7.4  Trustee's Disclaimer..............................................................................61
   Section 7.5  Notice of Default.................................................................................61
   Section 7.6  Reports by Trustee to Holders.....................................................................61
   Section 7.7  Compensation and Indemnity........................................................................62
   Section 7.8  Replacement of Trustee............................................................................63
   Section 7.9  Successor Trustee by Merger, Etc..................................................................63
   Section 7.10  Eligibility; Disqualification....................................................................64
   Section 7.11  Preferential Collection of Claims Against Company................................................64

ARTICLE EIGHT

DISCHARGE OF INDENTURE; DEFEASANCE................................................................................64

   Section 8.1  Termination of the Issuers' Obligations...........................................................64
   Section 8.2  Legal Defeasance and Covenant Defeasance..........................................................65
   Section 8.3  Conditions to Legal Defeasance or Covenant Defeasance.............................................66
   Section 8.4  Application of Trust Money........................................................................68
   Section 8.5  Repayment to the Issuers..........................................................................68
   Section 8.6  Reinstatement.....................................................................................69

ARTICLE NINE

AMENDMENTS, SUPPLEMENTS AND WAIVERS...............................................................................69

   Section 9.1  Without Consent of Holders........................................................................69
   Section 9.2  With Consent of Holders...........................................................................69
   Section 9.3  Effect on Senior Debt.............................................................................70
   Section 9.4  Compliance with TIA...............................................................................71
   Section 9.5  Revocation and Effect of Consents.................................................................71
</TABLE>

                                     (iii)

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   Section 9.6  Notation on or Exchange of Securities............................................................71
   Section 9.7  Trustee To Sign Amendments, Etc..................................................................72

ARTICLE TEN

SUBORDINATION OF SECURITIES......................................................................................72

   Section 10.1  Securities Subordinated to Senior Debt..........................................................72
   Section 10.2  Suspension of Payment When Senior Debt Is in Default............................................72
   Section 10.3  Securities Subordinated to Prior Payment of All Senior Debt on Dissolution, Liquidation or
                   Reorganization of an Issuer...................................................................73
   Section 10.4  Payments May Be Paid Prior to Dissolution.......................................................75
   Section 10.5  Holders To Be Subrogated to Rights of Holders of Senior Debt....................................75
   Section 10.6  Obligation of the Issuers Unconditional.........................................................75
   Section 10.7  Notice to Trustee...............................................................................75
   Section 10.8  Reliance on Judicial Order or Certificate of Liquidating Agent..................................76
   Section 10.9  Trustee's Relation to Senior Debt...............................................................76
   Section 10.10  Subordination Rights Not Impaired by Acts or Omissions of an Issuer or Holders of Senior Debt..77
   Section 10.11  Securityholders Authorize Trustee To Effectuate Subordination of Securities....................77
   Section 10.12  This Article Ten Not To Prevent Events of Default..............................................77
   Section 10.13  Trustee's Compensation Not Prejudiced..........................................................78

ARTICLE ELEVEN

GUARANTEE OF SECURITIES..........................................................................................78

   Section 11.1  Unconditional Guarantee.........................................................................78
   Section 11.2  Limitations on Guarantees.......................................................................79
   Section 11.3  Execution and Delivery of Guarantee.............................................................79
   Section 11.4  Release of a Guarantor..........................................................................80
   Section 11.5  Waiver of Subrogation...........................................................................80
   Section 11.6  Immediate Payment...............................................................................81
   Section 11.7  No Set-Off......................................................................................81
   Section 11.8  Obligations Absolute............................................................................81
   Section 11.9  Obligations Continuing..........................................................................81
   Section 11.10  Obligations Not Reduced........................................................................81
   Section 11.11  Obligations Reinstated.........................................................................82
   Section 11.12  Obligations Not Affected.......................................................................82
   Section 11.13  Waiver.........................................................................................83
   Section 11.14  No Obligation To Take Action Against the Issuers...............................................83
   Section 11.15  Dealing with the Issuers and Others............................................................83
   Section 11.16  Default and Enforcement........................................................................84
   Section 11.17  Amendment,Etc..................................................................................84
   Section 11.18  Acknowledgment.................................................................................84
</TABLE>

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<S>              <C>                                                                                          <C>
   Section 11.19  Costs and Expenses..............................................................................84
   Section 11.20  No Merger or Waiver; Cumulative Remedies........................................................84
   Section 11.21  Survival of Obligations.........................................................................84
   Section 11.22  Guarantee in Addition to Other Obligations......................................................85
   Section 11.23  Severability....................................................................................85
   Section 11.24  Successors and Assigns..........................................................................85

ARTICLE TWELVE

SUBORDINATION OF GUARANTEE........................................................................................85

   Section 12.1  Guarantee Obligations Subordinated to Guarantor Senior Debt......................................85
   Section 12.2  Suspension of Guarantee Obligations When Guarantor Senior Debt Is in Default.....................85
   Section 12.3  Guarantee Obligations Subordinated to Prior Payment of All Guarantor Senior Debt on Dissolution,
                   Liquidation or Reorganization of Such Guarantor................................................86
   Section 12.4  Payments May Be Paid Prior to Dissolution........................................................87
   Section 12.5  Holders of Guarantee Obligations To Be Subrogated to Rights of Holders of Guarantor Senior Debt..87
   Section 12.6  Obligations of the Guarantors Unconditional......................................................88
   Section 12.7  Notice to Trustee................................................................................88
   Section 12.8  Reliance on Judicial Order or Certificate of Liquidating Agent...................................89
   Section 12.9  Trustee's Relation to Guarantor Senior Debt......................................................89
   Section 12.10  Subordination Rights Not Impaired by Acts or Omissions of the Guarantors or Holders of Guarantor
                   Senior Debt....................................................................................89
   Section 12.11  Holders Authorize Trustee To Effectuate Subordination of Guarantee Obligations..................90
   Section 12.12  This Article Twelve Not To Prevent Events of Default............................................90
   Section 12.13  Trustee's Compensation Not Prejudiced...........................................................90

ARTICLE THIRTEEN

MISCELLANEOUS.....................................................................................................90

   Section 13.1  TIA Controls.....................................................................................90
   Section 13.2  Notices..........................................................................................90
   Section 13.3  Communications by Holders with Other Holders.....................................................92
   Section 13.4  Certificate and Opinion as to Conditions Precedent...............................................92
   Section 13.5  Officers' Certificates and Opinions of Counsel...................................................92
   Section 13.6  Rules by Trustee, Paying Agent, Registrar........................................................93
   Section 13.7  Legal Holidays...................................................................................93
   Section 13.8  Governing Law....................................................................................93
   Section 13.9  No Adverse Interpretation of Other Agreements....................................................93
   Section 13.10  No Recourse Against Others......................................................................93
   Section 13.11  Successors......................................................................................93
   Section 13.12  Duplicate Originals.............................................................................93
</TABLE>

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<TABLE>
<CAPTION>

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<S>              <C>                                                                                          <C>
   Section 13.13  Severability...................................................................................93
   Section 13.14  References to Parent's Board of Directors......................................................94
</TABLE>

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<PAGE>   134

                                                                            Page
                                                                            ----

EXHIBITS
   EXHIBIT A - Form of Security
   EXHIBIT B - Form of Legends
   EXHIBIT C - Form of Certificate to be Delivered in Connection with
                  Transfers to Non-QIB Accredited Investors
   EXHIBIT D - Form of Certificate to be Delivered in Connection with
                  Transfers Pursuant to Regulation S
   EXHIBIT E - Form of Guarantee

                                     (vii)

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