<PAGE>

                                                                   EXHIBIT 10.27

                             STOCKHOLDERS AGREEMENT
                             ----------------------

         STOCKHOLDERS AGREEMENT dated as of November 20, 2001 by and among
Concentra Inc., a Delaware corporation (the "Company"), Welsh, Carson, Anderson
                                             -------
& Stowe VIII, L.P., a Delaware limited partnership ("WCAS"), and the other
                                                     ----
holders of Common Stock, $.01 par value, of the Company ("Common Stock") and
                                                          ------------
warrants to purchase Common Stock ("Warrants") named on Schedule I hereto (each
                                    --------
a "WCAS Holder" and collectively, the "WCAS Holders"), the several stockholders
   -----------                         ------------
of National Health Resources, Inc., a Delaware corporation ("NHR") named on
                                                             ---
Schedule II hereto (each an "NHR Holder" and collectively, the "NHR Holders")
                             ----------                         ----------
and, solely for purposes of Section 6 hereof, Ferrer Freeman Thompson & Co., LLC
("FFT"), on behalf of itself and its Designated Affiliates (as hereinafter
  ---
defined).

                              W I T N E S S E T H:
                              - - - - - - - - - -

         WHEREAS, the Company, NHR Acquisition Company, Inc., a Delaware
corporation and wholly-owned subsidiary of the Company ("Merger Corp"), and NHR
                                                         -----------
are parties to a Merger Agreement dated as of November 2, 2001 (the "Merger
                                                                     ------
Agreement"), pursuant to which, at the Effective Time (such term being used in
---------
this Agreement as defined in the Merger Agreement), Merger Corp will be merged
(the "Merger") with and into NHR with NHR surviving the Merger as a wholly-owned
      -----
subsidiary of the Company;

         WHEREAS, pursuant to and in accordance with the Merger Agreement, at
the Effective Time all shares of capital stock of NHR held by the NHR Holders
shall be converted into the right to receive cash and/or shares of Common Stock
(such shares, the "Common Shares"); and
                   -------------

         WHEREAS, the Company, WCAS, the other WCAS Holders, the NHR Holders and
FFT desire to provide for certain matters relating to the Common Shares;

         NOW, THEREFORE, in consideration of the premises and of the mutual
covenants and agreements herein contained, the parties hereto hereby agree as
follows:

         SECTION 1. Certain Defined Terms. In addition to the terms defined
                    ---------------------
elsewhere herein, the following terms shall have the following meanings when
used herein with initial capital letters:

         "Affiliate" shall mean, with respect to any Person, any other Person
          ---------
that directly or indirectly through one or more intermediaries, controls, or is
controlled by, or is under common control with, such Person.

         "Agreement" shall mean this agreement, as the same may be amended,
          ---------
supplemented or otherwise modified from time to time in accordance with the
terms hereof.

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         "Assumption Agreement" shall mean a writing reasonably satisfactory in
          --------------------
form and substance to the Company and a majority in interest of the WCAS Holders
(determined by reference to holdings of Common Stock) whereby a Permitted
Transferee of an NHR Holder becomes a party to and agrees to be bound by (i) the
terms of this Agreement as an "NHR Holder" hereunder to the same extent as if it
was an original party hereto and (ii) the terms of any lock-up agreement to
which the transferee is party.

         "Business Day" shall mean a day other than a Saturday, Sunday, federal
          ------------
or New York State holiday or other day on which commercial banks in New York
City are authorized or required by law to close.

         "Commission" shall mean the Securities and Exchange Commission, or any
          ----------
other federal agency at the time administering the Securities Act.

         "Designated Affiliate" means, in the case of WCAS or FFT, (i) any
          --------------------
Affiliate thereof, (ii) any general or limited partner thereof, (iii) any
managing director, general partner, director, limited partner, officer or
employee thereof or of any Affiliate thereof, or the heirs, executors,
administrators, testamentary trustees, legatees or beneficiaries of any of the
foregoing persons referred to in this clause (iii) ("Designated Associates"), or
                                                     ---------------------
(iv) a trust, the beneficiaries of which, or a corporation, limited liability
company or partnership, the stockholders, members of general or limited partners
of which, include only WCAS, FFT, any Affiliates of WCAS or FFT, or any
Designated Associates or the spouses or lineal descendants thereof.

         "Exchange Act" shall mean the Securities Exchange Act of 1934, as
          ------------
amended, or any successor federal statute and the rules and regulations of the
Commission promulgated thereunder, all as the same shall be in effect at the
time.

         "Period of Distribution" shall mean (i) with respect to any Public
          ----------------------
Offering of Common Stock which includes Registrable Stock pursuant to Section
7(a), the period beginning on the effective date of the registration statement
relating thereto and ending on the first date on which each underwriter has
completed the distribution of all Registrable Stock purchased by it and (ii)
with respect to any other registration of Registrable Stock pursuant to Section
7(a), a 90 day period beginning on the effective date of the registration
statement relating thereto.

         "Permitted Transferee" shall mean (i) with respect to any NHR Holder
          --------------------
who is an individual, the spouse or lineal descendants thereof or any trust for
the benefit of such NHR Holder or spouse or lineal descendants and (ii) with
respect to any NHR Holder that is not an individual, any Affiliate thereof.

         "Person" shall mean any individual, corporation, limited liability
          ------
company, partnership, trust, joint stock company, business trust, unincorporated
association, joint venture, governmental authority or other legal entity of any
nature whatsoever.

         "Public Offering" shall mean the sale of Common Stock to the public in
          ---------------
a firm commitment underwritten public offering pursuant to an effective
registration statement (other

                                       2

<PAGE>

 than a registration statement on Form S-4 or S-8
or any similar or successor form) filed under the Securities Act.

         "Registrable Stock" shall mean the Common Shares; provided, that as to
          -----------------
any particular Common Shares otherwise constituting Registrable Stock, such
shares shall cease to be Registrable Stock when (A) a registration statement
with respect to the sale of such shares shall have become effective under the
Securities Act and such shares shall have been disposed of in accordance with
such registration statement, (B) such shares shall have been distributed to the
public pursuant to Rule 144 (or any successor provision) under the Securities
Act, (C) such shares shall have become eligible for resale pursuant to Rule
144(k) (or any successor provision under the Securities Act), (D) such shares
shall have been otherwise Transferred and new certificates for them not bearing
a legend restricting further Transfer shall have been delivered to the
transferee by the Company and subsequent disposition of them by the transferee
shall not require registration or qualification of them under the Securities Act
or (E) they shall have ceased to be outstanding.

         "Registration Expenses" shall mean all expenses incurred by the Company
          ---------------------
in complying with Section 7 hereof, including, without limitation, all
registration, listing and filing fees, printing expenses, fees and disbursements
of counsel and independent public accountants for the Company, fees of the
National Association of Securities Dealers, Inc. and fees of transfer agents and
registrars, but excluding any Selling Expenses.

         "Securities Act" shall mean the Securities Act of 1933, as amended, or
          --------------
any successor federal statute and the rules and regulations of the Commission
promulgated thereunder, all as the same shall be in effect at the time.

         "Selling Expenses" shall mean all underwriting discounts and selling
          ----------------
commissions applicable to the sale of Registrable Stock and all expenses of
counsel to the selling holders of Registrable Stock.

         "Transfer" shall mean a transfer, sale, assignment, pledge,
          --------
hypothecation or other disposition, whether directly or indirectly pursuant to
the creation of a derivative security, the grant of an option or other right,
the imposition of a restriction on disposition or voting, or transfer by
operation of law.

         SECTION 2. Transfer of Common Shares.
                    -------------------------

         (a) Restrictions on Transfer; Permitted Transfers. Until August 17,
             ---------------------------------------------
2004 (the "Section 2(a) Expiration Date"), no NHR Holder shall Transfer any
           ----------------------------
Company Shares to any Person; provided, that this Section 2(a) shall not
                              --------
restrict (A) any Transfer made pursuant to Section 3, 4 or 7 hereof, (B) any
Transfer to a Permitted Transferee of such NHR Holder who duly executes and
delivers an Assumption Agreement so long as such Transfer is made for no more
than cost and otherwise complies with the terms and conditions of this Agreement
or (C) any Transfer of Company Shares held by any employee, officer or director
of the Company or any subsidiary of the Company in connection with the
repurchase of such shares by the Company (the Transfers described in the
foregoing clauses (A), (B) and (C) being herein referred

                                       3

<PAGE>

to as "Permitted Transfers"). Any purported Transfer of any Company Shares in
       -------------------
violation of the provisions of this Agreement shall be null and void and of no
effect and each party hereto agrees that the Company shall not give effect to
any such Transfer. Notwithstanding anything to the contrary contained above, no
Transfer otherwise permitted under this Section 2(a) shall be permitted if such
Transfer would require the Company to register a class of equity securities
under Section 12 of the Exchange Act under circumstances where the Company does
not then have securities of such class registered under Section 12 of the
Exchange Act.

         (b) Notice of Proposed Transfer; Securities Law Compliance. Prior to
             ------------------------------------------------------
any proposed Transfer of any Common Shares (other than under the circumstances
described in Sections 3, 4 or 7 hereof), whether such Transfer is made before or
after the Section 2(a) Expiration Date, the NHR Holder holding such shares shall
give written notice to the Company of its intention to effect such Transfer.
Each such notice shall describe the manner of the proposed Transfer and, if
reasonably requested by the Company, shall be accompanied by an opinion of
counsel reasonably satisfactory to the Company to the effect that the proposed
Transfer of such Common Shares may be effected without registration under the
Securities Act. If the foregoing condition is met, such NHR Holder shall be
entitled, subject to the other terms and condition of this Agreement, to
Transfer such shares in accordance with the terms of its notice. Each
certificate for Common Shares Transferred as above provided shall bear the
Securities Act Legend set forth in Section 2(c) below, unless (i) such Transfer
is in accordance with the provisions of Rule 144 (or any other rule permitting
public sale without registration under the Securities Act) or is pursuant to an
effective registration under the Securities Act or (ii) the opinion of counsel
referred to above is to the further effect that (or, if no opinion is required,
the Company determines that) the transferee and any subsequent transferee (other
than an Affiliate of the Company) would be entitled to Transfer such securities
in a public sale without registration under the Securities Act. The foregoing
restrictions on transferability of Company Shares shall terminate as to any
particular shares when such shares have either (A) been sold to the public
pursuant to an effective registration statement under the Securities Act or (B)
whenever the holder of such shares is able to demonstrate to the Company (and
its counsel) that the provisions of Rule 144(k) of the Securities Act are
available to such NHR Holder without limitation. Upon the termination of such
restrictions, such holder shall be entitled to receive from the Company, without
expense, a new certificate not bearing the Securities Act Legend set forth in
Section 2(c).

         (c) Legends. Each certificate representing Company Shares shall bear
             -------
the following two legends each in substantially the following form with such
additions thereto or changes therein as the Company may be advised by counsel
are required by law or necessary to give full effect to this Agreement (the
first such legend being referred to herein as the "Securities Act Legend" and
                                                   ---------------------
the second such legend being referred to herein as the "Shareholders Agreement
                                                        ----------------------
Legend"):
------

         "THE SHARES OF COMMON STOCK EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN
         REGISTERED UNDER THE SECURITIES ACT OF 1933, AND MAY NOT BE SOLD,
         TRANSFERRED OR OTHERWISE DISPOSED OF UNLESS THEY HAVE BEEN REGISTERED

                                       4

<PAGE>

         UNDER THAT ACT OR AN EXEMPTION FROM REGISTRATION IS AVAILABLE."

         "THE SHARES OF COMMON STOCK REPRESENTED BY THIS CERTIFICATE ARE SUBJECT
         TO A STOCKHOLDERS AGREEMENT DATED AS OF NOVEMBER 20, 2001 AMONG THE
         COMPANY AND THE STOCKHOLDERS OF THE COMPANY NAMED THEREIN, AS AMENDED,
         A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF THE COMPANY. NO
         TRANSFER, SALE, ASSIGNMENT, PLEDGE, HYPOTHECATION OR OTHER DISPOSITION
         OF THE SECURITIES REPRESENTED BY THIS CERTIFICATE MAY BE MADE EXCEPT IN
         ACCORDANCE WITH THE PROVISIONS OF SUCH STOCKHOLDERS AGREEMENT. THE
         HOLDER OF THIS CERTIFICATE, BY ACCEPTANCE OF THIS CERTIFICATE, AGREES
         TO BE BOUND BY ALL OF THE PROVISIONS OF SUCH STOCKHOLDERS AGREEMENT."

The Shareholders Agreement Legend will be removed by the Company by the delivery
of substitute certificates without such legend in the event of (i) a Transfer
permitted by this Agreement and in which the transferee is not required to enter
into an Assumption Agreement or (ii) the termination of this Agreement pursuant
to the terms hereof.

         SECTION 3. Tag-Along Rights.
                    ----------------

         (a) With respect to any proposed Transfer by one or more WCAS Holders
(collectively, the "Selling Stockholder") of shares of Common Stock and/or
                    -------------------
Warrants to any Person who is not an Affiliate thereof (including as Affiliates
for such purposes all Designated Affiliates of WCAS and (i) with respect to each
WCAS Holder that is a partnership, (A) the general and limited partners thereof
and (B) all officers, directors, members and employees of each Affiliate thereof
and (ii) with respect to each WCAS Holder who is an individual, any spouse or
lineal descendant thereof and any trust for the benefit of such WCAS Holder or
any such spouse or lineal descendant), other than (i) in a Public Offering, (ii)
pursuant to a bona fide sale to the public pursuant to Rule 144 under the
Securities Act or (iii) pursuant to any agreement or plan of merger or
combination, including any tender or exchange offer in respect thereof, that is
approved by the Board of Directors of the Company and that provides for equal
treatment of all outstanding shares of Common Stock (any such transaction, other
than those referred to in (i), (ii) and (iii) above, a "Proposed Sale"), each
                                                        -------------
NHR Holder will have the right to require the proposed transferee or acquiring
Person to purchase from each such NHR Holder who exercises its rights under this
Section 3 (a "Tagging NHR Holder") up to that number of Common Shares that is
              ------------------
equal to the product (rounded down to the nearest whole number) of (i) the
quotient determined by dividing (A) the aggregate number of Common Shares owned
by such Tagging Stockholder by (B) the aggregate number of shares of Common
Stock and Class A Common Stock, $.01 par value, of the Company ("Class A Common
                                                                 --------------
Stock" and, together with the Common Stock, "Company Capital Stock") then
-----                                        ---------------------
outstanding (assuming the exercise of all outstanding Warrants) and owned by the
Selling Stockholder, the Tagging NHR Holders and all other securityholders of
the Company having a right to participate in such Proposed Sale and (ii) the
total number of shares of Common Stock and Warrants proposed to be Transferred
to the

                                       5

<PAGE>

transferee or acquiring Person in the Proposed Sale (a "Proposed Transferee"),
                                                        -------------------
at the same price per share of Common Stock and upon the same terms and
conditions (including, without limitation, time of payment, form of
consideration and adjustments to purchase price) as the Selling Stockholder;
provided, that in order to be entitled to exercise its right to sell Common
--------
Shares to the Proposed Transferee pursuant to this Section 3, each Tagging
Stockholder (x) shall agree to the same covenants (as appropriate) and
indemnities as the Selling Stockholder agrees to in connection with the Proposed
Sale; provided, that the aggregate amount of liability of such Tagging NHR
      -------
Stockholder with respect to such covenants and indemnities shall not exceed the
proceeds to such Tagging NHR Stockholder in connection with the Proposed Sale,
and (y) shall make such representations and warranties concerning its title to
the Company Shares to be sold in connection with the Proposed Sale and its
authority to enter into and consummate the Proposed Sale as the Selling
Stockholder makes, but shall not be required to make any other representations
and warranties.

         (b) Each Tagging NHR Stockholder will be responsible for funding its
proportionate share of any escrow arrangements in connection with the Proposed
Sale and for its proportionate share of any withdrawals therefrom, including
without limitation any such withdrawals that are made with respect to claims
arising out of agreements, covenants, representations, warranties, indemnities
or other provisions relating the Proposed Sale that were made by the Tagging NHR
Stockholder.

         (c) Each Tagging NHR Stockholder will be responsible for its
proportionate share of the reasonable fees, commissions and other out-of-pocket
expenses (collectively, "Costs") of the Proposed Sale to the extent not paid or
reimbursed by the Company, the Proposed Transferee or another Person (other than
the Selling Stockholder); provided, that the Proposed Sale is consummated and
                          --------
the liability for such Costs shall not exceed the total purchase price received
by such Tagging NHR Stockholder for such shares. The Selling Stockholder shall
be entitled to estimate the Tagging NHR Stockholders' proportionate share of
such Costs and to withhold such amounts from payments to be made to the Tagging
NHR Stockholder at the time of closing of such Proposed Sale; provided, that (i)
                                                              --------
such estimate shall not preclude the Selling Stockholder from recovering
additional amounts from the Tagging NHR Stockholder in respect of such Tagging
NHR Stockholder's proportionate share of such Costs and (ii) the Selling
Stockholder shall reimburse the Tagging NHR Stockholder to the extent actual
amounts are ultimately less than the estimated amounts or any such amounts are
paid by the Company, the Proposed Transferee or another Person (other than the
Selling Stockholder).

         (d) The Selling Stockholder will give notice to the Company of each
Proposed Sale not more than five days after the execution of the definitive
agreement relating to the Proposed Sale, setting forth the number of shares of
Common Stock and Warrants proposed to be so Transferred, the name and address of
the Proposed Transferee, the proposed amount and form of consideration (and if
such consideration consists in part or in whole of property other than cash, the
Selling Stockholder will provide such information, to the extent reasonably
available to the Selling Stockholder, relating to such non-cash consideration as
each of the Tagging NHR Stock holders, may reasonably request in order to
evaluate such non-cash consideration) and other terms and conditions of payment
offered by the Proposed Transferee. If any holders of Common Stock are given an
option as to the form and amount of consideration to be received, all

                                        6

<PAGE>

Tagging NHR Stockholders shall be given the same option. In the event that any
of the terms and/or conditions set forth in the notice are thereafter amended in
any respect, the Selling Stockholder shall also give written notice of the
amended terms and conditions of the Proposed Sale to the Company, and each
Tagging NHR Stockholder shall be permitted to cancel its exercise of its rights
under this Section 3 upon delivery of written notice to the Company to such
effect and shall be released from its obligation hereunder. Upon its receipt of
any such notice or amended notice, the Company shall promptly, but in all events
within three (3) Business Days of its receipt thereof, forward copies thereof to
each of the Tagging NHR Stockholders. The Selling Stock holder will deliver or
cause to be delivered to the Company, which in turn will deliver to each Tagging
NHR Stockholder, copies of all transaction documents relating to the Proposed
Sale promptly as the same become available. The tag-along rights provided by
this Section 3 must be exercised by the Tagging NHR Stockholders within 10
Business Days following receipt of the notice required by the preceding sentence
by delivery of a written notice to the Selling Stock holder indicating its
desire to exercise its rights and specifying the number of Common Shares it
desires to sell (the "Tag-Along Notice"). The Tagging NHR Stockholders will be
                      ----------------
entitled under this Section 3 to Transfer to the Proposed Transferee up to that
number of Common Shares calculated in accordance with Section 3(a) above.

         (e) Any Tagging NHR Stockholder participating in the proposed
disposition shall deliver to the Company, as agent for such Tagging NHR
Stockholder, for Transfer to the Proposed Transferee one or more certificates,
properly endorsed for Transfer and with all stock transfer taxes paid and stamps
affixed, which represent the number of Common Shares that such Tagging NHR
Stockholder elects to dispose of pursuant to this Section 3. The consummation of
such proposed disposition shall be subject to the sole discretion of the Selling
Stock holder, who shall have no liability or obligation whatsoever to any
Tagging NHR Stockholder participating therein other than to obtain for such
Tagging NHR Stockholder the same terms and conditions as those of the Selling
Stockholder. Upon the consummation of any such sale, the Company (i) shall
transfer to the Proposed Transferee a stock certificate or certificates
representing the number of Common Shares to be disposed of by any Tagging NHR
Stockholders and (ii) shall promptly thereafter remit to each Tagging NHR
Stockholder (i) that portion of the proceeds of the disposition to which such
Tagging NHR Stockholder is entitled by reason of such participation and (ii) a
stock certificate representing any balance of Common Shares that were not so
disposed of (or all Common Shares, in the event the proposed disposition is not
consummated).

         (f) If any Tagging NHR Stockholder exercises its rights under this
Section 3, the closing of the purchase of the Common Shares with respect to
which such rights have been exercised will take place concurrently with the
closing of the sale of the Selling Stockholder's Common Stock and/or Warrants to
the Proposed Transferee. If by the end of ninety (90) days following the date of
delivery of the notice of the Proposed Sale provided by the Company pursuant to
Section 3(d), the Selling Stockholder and the Proposed Transferee have not
completed the Proposed Sale, each Tagging NHR Stockholder shall be released from
its obligations under this Section 3, and the Tag-Along Notices shall be null
and void, and it shall be necessary for the terms of this Section 3 to be
separately complied with in order to consummate such Proposed Sale pursuant to
this Section 3.

                                       7

<PAGE>

         SECTION 4. Drag-Along Rights.
                    -----------------

         (a) If one or more of the WCAS Holders (collectively, the "Dragging
                                                                    --------
Stockholder") receives an offer from a Person other than an Affiliate thereof (a
-----------
"Third Party") to purchase (in a transaction of a type referred to in the first
 -----------
sentence of Section 3(a)) at least a majority of the shares of Common Stock then
outstanding and such offer is accepted by the Dragging Stockholder, then each
NHR Holder (collectively, the "Drag-Along Stockholders") hereby agrees that, if
                               -----------------------
requested by the Dragging Stockholder, it will Transfer to such Third Party,
subject to the other provisions of this Section 4, on the terms of the offer so
accepted by the Dragging Stockholder, including, without limitation, time of
payment, form and choice of consideration and adjustments to purchase price, a
number of Common Shares equal to the number of Common Shares owned by it
multiplied by the percentage of the then outstanding shares of Common Stock to
which the Third Party offer is applicable.

         (b) The Dragging Stockholder will give notice (the "Drag-Along Notice")
                                                             -----------------
to the Company of any proposed Transfer giving rise to the rights of the
Dragging Stockholder set forth in Section 4(a) (a "Section 4 Transfer") within
                                                   ------------------
five (5) Business Days following the Dragging Stockholder's acceptance of the
offer referred to in Section 4(a). The Company will promptly forward such notice
to each Drag-Along Stockholder (it being understood that such notice shall be
given to the Company and forwarded to the Drag-Along Stockholders, in any event,
not less than 10 Business Days prior to the proposed closing date for such
Section 4 Transfer). The Drag-Along Notice will set forth the number of shares
of Common Stock proposed to be so Transferred, the name of the proposed
Transferee or acquiring Person, the proposed amount and form of consideration
(and if such consideration consists in part or in whole of property other than
cash, the Dragging Stockholder will provide such information, to the extent
reasonably available to the Dragging Stockholder, relating to such non-cash
consideration as the Drag-Along Stockholders together may reasonably request in
order to evaluate such non-cash consideration) and the other terms and
conditions of the offer. If any holders of Common Stock are given an option as
to the form and amount of consideration to be received, all Drag-Along Holders
shall be given the same option. Each Drag-Along Stockholder (x) shall agree to
the same covenants (as appropriate) and indemnities as the Dragging Stockholder
agrees to in connection with the Section 4 Transfer; provided, that the
                                                     --------
aggregate amount of liability of such Drag-Along Stockholder with respect to
such covenants and indemnities shall not exceed the proceeds to such Drag-Along
Stockholder in connection with the Section 4 Transfer and (y) shall make such
representations and warranties concerning its title to the Common Shares to be
sold in connection with the Section 4 Transfer and its authority to enter into
and consummate the Section 4 Transfer as the Dragging Stockholder makes, but
shall not be required to make any other representations and warranties. If a
Dragging Stockholder does not request that the Drag-Along Stockholders
participate in a Section 4 Transfer, then each NHR Holder shall have the right
to participate in such proposed transfer in accordance with its rights under
Section 3 above.

         (c) Each Drag-Along Stockholder will be responsible for funding its
proportionate share of any escrow arrangements in connection with the Section 4
Transfer and for its proportionate share of any withdrawals therefrom, including
without limitation any such withdrawals that are made with respect to claims
arising out of agreements, covenants, represen-

                                       8

<PAGE>

tations, warranties, indemnities or other provisions relating the Section 4
Transfer that were made by the Drag-Along Stockholder.

         (d) Each Drag-Along Stockholder will be responsible for its
proportionate share of the Costs of the Section 4 Transfer to the extent not
paid or reimbursed by the Company, the Third Party or another Person (other than
the Dragging Stockholder); provided, that such Section 4 Transfer is consummated
                           --------
and the liability for such Costs shall not exceed the total purchase price
received by such Drag-Along Stockholder for such shares. The Dragging
Stockholder shall be entitled to estimate the Drag-Along Stockholders'
proportionate share of such Costs and to withhold such amounts from payments to
be made to the Drag-Along Stockholder at the time of closing of the Section 4
Transfer; provided, that (i) such estimate shall not preclude the Dragging
Stockholder from recovering additional amounts from the Drag-Along Stockholder
in respect of such Drag-Along Stockholder's proportionate share of such Costs
and (ii) the Dragging Stockholder shall reimburse the Drag-Along Stockholder to
the extent actual amounts are ultimately less than the estimated amounts or any
such amounts are paid by the Company, the Third Party or another Person (other
than the Dragging Stockholder). If the Section 4 Transfer is not consummated
within 180 days from the date of the Drag-Along Notice, the Dragging Stockholder
must deliver another Drag-Along Notice in order to exercise its rights under
this Section 4 with respect to such Section 4 Transfer.

         (e) At the closing of such Section 4 Transfer, each of the Dragging
Stockholders shall deliver certificates evidencing the Common Shares then held
by it and to be sold in such sale, duly endorsed for transfer or accompanied by
stock powers executed in blank, against payment of the purchase price therefor
by wire transfer to the account or accounts specified by such Drag-Along
Stockholder.

         (f) The proceeds from such Section 4 Transfer shall be allocated among
all selling holders of Common Stock on a pro rata basis, based on the number of
shares of Common Stock then held by each such stockholder.

         SECTION 5. Custody Agreement and Power of Attorney. Upon delivering a
                    ---------------------------------------
Tag Along Notice or receiving a Drag-Along Notice, each NHR Holder will, if
requested by the Selling Stockholder or the Dragging Stockholder, as the case
may be, execute and deliver a custody agreement and power of attorney in form
and substance reasonably satisfactory to the Selling Stockholder or the Dragging
Stockholder with respect to the Common Shares that are to be sold by such NHR
Holders pursuant to Section 3 or Section 4, as the case may be (a "Custody
                                                                   -------
Agreement and Power of Attorney"). The Custody Agreement and Power of Attorney
-------------------------------
will provide, among other things, that each such NHR Holder will deliver to and
deposit in custody with the custodian and attorney-in-fact named therein a
certificate or certificates representing such Common Shares (each duly endorsed
in blank by the registered owner or owners thereof) and irrevocably appoint said
custodian and attorney-in-fact as its agent and attorney-in-fact with full power
and authority to act under the Custody Agreement and Power of Attorney on its
behalf with respect to (and subject to the terms and conditions of) the matters
specified in Section 3 or Section 4, as the case may be.

         SECTION 6. Right of First Offer.
                    --------------------

                                       9

<PAGE>

         (a) If, at any time after the Section 2(a) Expiration Date, any NHR
Holder (for purposes of this Section 6, a "Seller") desires to Transfer (other
                                           -----
than in a Permitted Transfer) any of the Common Shares held by it, then such
Seller shall give to the Company a written notice (a "Notice of Desire to Sell")
                                                      ------------------------
which shall set forth in reasonable detail the number of Common Shares which it
desires to sell (the "Subject Shares") and, may, if the Seller so chooses to
specify, set forth any other terms and conditions of the desired disposition.
The Company shall deliver such Notice of Desire to Sell to WCAS and FFT promptly
upon receipt thereof. A Seller may deliver a Notice of Desire to Sell whether or
not such Seller has received an offer from a third party to purchase such
Company Shares.

         (b) WCAS, FFT and their Designated Affiliates (the "Offerees") shall
                                                             --------
have the right, exercisable upon written notice to the Seller within 15 days
after receipt of any Notice of Desire to Sell (the "Offer Notice"), to offer to
                                                    ------------
purchase any or all Subject Shares proposed to be sold by the Seller at a
purchase price equal to the proposed purchase price specified in the Notice of
Desire to Sell if so specified, or as proposed in the Offer Notice if not
specified in the Notice of Desire to Sell, and otherwise on the terms and
conditions specified in the Notice of Desire to Sell to the extent so specified
and any additional terms and conditions proposed in the Offer Notice
(collectively, including with respect to purchase price, the "Offer Terms").
                                                              -----------
Each Offer Notice shall state the number of shares to be purchased by the
Offerees delivering such Offer Notice (the "Purchasing Stockholders") and that
                                            -----------------------
the Purchasing Stockholders will purchase such shares within 45 days thereafter
(or such longer period as is necessary to obtain any necessary consents or
approvals or to otherwise comply with applicable law). In the event that more
than one Person exercises its right to offer to purchase pursuant to this
paragraph 6(b), the allocation among such Purchasing Stockholders of any shares
actually sold pursuant to this paragraph 6(b) shall be as agreed by such
Purchasing Stockholders; provided, that, if the number of shares that the
Purchasing Stockholders offer to purchase exceeds the number of Subject Shares
and the Purchasing Stockholders do not agree on the allocation of the Subject
Shares prior to the expiration of the 15-day period specified in this paragraph
6(b) then the Subject Shares shall be allocated ratably between Purchasing
Stockholders based on the number of shares of Company Capital Stock owned by
such Purchasing Stockholder on the date of such Offer Notice out of the total
outstanding shares of Company Capital Stock on that date owned by all of the
Purchasing Stockholders; provided, further, that any such Subject Shares
                         --------  -------
allocated to the FFT and its Designated Affiliates may be allocated among the
they as they may agree.

         (c) If the Offerees deliver, within the period specified in paragraph
6(b) above, an Offer Notice with respect to Subject Shares, the Seller shall
sell such Subject Shares to such Purchasing Stockholders on the Offer Terms
within the 45-day period specified in paragraph 6(b) above (or such longer
period as is necessary to obtain any necessary consents or approvals or to
otherwise comply with applicable law). Following the period specified in
paragraph 6(b) above, the Seller may (subject to any other applicable
restrictions hereunder) Transfer such Subject Shares with respect to which no
Offer Notice was received to any third party; provided, that the Seller may not
sell such shares with respect to which no Offer Notice was received to such
third party on material terms that are the same as or more favorable, in the
aggregate, to such third party than the material terms set forth in the Offer
Terms, in the aggregate. Any such sale with respect to which definitive
documentation is not entered into within 60 days after the

                                       10

<PAGE>

expiration of the period specified in paragraph 6(b) above, or which is not
consummated within 60 days of the execution of such definitive documentation (or
such longer period as is necessary to obtain any necessary consents or approvals
or to otherwise comply with applicable law) shall again be subject to the
requirements of this Section 6.

         SECTION 7. Registration Rights.
                    -------------------

         (a) Piggyback Registration. If the Company at any time proposes to
             ----------------------
register any Common Stock under the Securities Act for sale to the public,
whether for its own account or for the account of other stockholders of the
Company or both (except (x) with respect to registration statements on Form S-4
or S-8 or another form not available for registering Registrable Stock for sale
to the public or (y) with respect to the first Public Offering after the date
hereof), it will give written notice at such time to all holders of outstanding
Registrable Stock of its intention to do so. Upon the written request of any
such holder, given within 20 days after receipt of any such notice by the
Company, to register any of its Registrable Stock (which request shall state the
intended method of disposition thereof), the Company will use its reasonable
best efforts to cause the Registrable Stock as to which registration shall have
been so requested to be included in the securities to be covered by the
registration statement proposed to be filed by the Company, all to the extent
required to permit the sale or other disposition by the holder (in accordance
with its written request) of such Registrable Stock so registered; provided that
nothing herein shall prevent the Company from abandoning or delaying such
registration at any time. In the event that any registration pursuant to this
Section 7(a) shall be in whole or in part an underwritten public offering of
Common Stock, any request by a holder pursuant to this Section 7(a) to register
Registrable Stock shall specify that such Registrable Stock is to be included in
the underwriting on the same terms and conditions as the shares of Common Stock
otherwise being sold through underwriters under such registration. The number of
shares of Registrable Stock to be included in such an underwriting may be
reduced (such reduction to be made on a pro rata basis among the holders of
Registrable Stock requesting registration pursuant to this Section 7(a) based on
the number of shares of Registrable Stock requested to be registered by such
holders) if and to the extent that the managing underwriter shall be of the
opinion that such inclusion would adversely affect the marketing of the
securities to be sold therein by the Company and/or any other selling
securityholders of the Company.

         (b) Registration Procedures. If and whenever the Company is required by
             -----------------------
the provisions of Section 7(a) hereof to use its reasonable best efforts to
effect the registration of any of the Registrable Stock held by NHR Holders
under the Securities Act, the Company will:

         (i) in accordance with the Securities Act and all applicable rules and
regulations, prepare (and afford one counsel for the selling holders of
Registrable Stock reasonable opportunity to review and comment thereon) and file
with the Commission a registration statement with respect to such securities and
use its reasonable best efforts to cause such registration statement to become
and remain effective for the Period of the Distribution contemplated thereby;

         (ii) prepare (and afford one counsel for the selling holders of
Registrable Stock reasonable opportunity to review and comment thereon) and file
with the Commission such

                                       11

<PAGE>

amendments and supplements to such registration statement and the prospectus
used in connection therewith and any documents incorporated by reference therein
and file such other documents as may be necessary to keep such registration
statement effective for the Period of the Distribution contemplated thereby and
to comply with the provisions of the Securities Act with respect to the
disposition of all Registrable Stock covered by such registration statement in
accordance with the sellers' intended method of disposition set forth in such
registration statement for such Period of Distribution;

         (iii) furnish to each selling holder and to each underwriter such
number of copies of the registration statement and the prospectus included
therein (including each preliminary prospectus), and all amendments,
supplements, and exhibits thereto, and such other documents as such persons may
reasonably request in order to facilitate the public sale or other disposition
of the Registrable Stock covered by such registration statement;

         (iv) use its reasonable best efforts to register or qualify the
Registrable Stock covered by such registration statement under the securities or
blue sky laws of such jurisdictions as the selling holders of Registrable Stock
or, in the case of an underwritten public offering, the managing underwriter,
shall reasonably request; provided, that the Company will not be required to (A)
qualify generally to do business in any jurisdiction where it would not
otherwise be required to qualify but for this paragraph (iv), (B) subject itself
to taxation in any such jurisdiction or (C) consent to general service of
process in any jurisdiction;

         (v) immediately notify each selling holder of Registrable Stock under
such registration statement and each underwriter (A) when such registration
statement or any post- effective amendment or supplement thereto becomes
effective or a supplement to any prospectus forming a part of such registration
statement has been filed; (B) of the issuance by the Commission or any state
securities authority of any stop order, injunction or other order or requirement
suspending the effectiveness of such registration statement; (C) of the
happening of any event as a result of which such registration statement, as then
in effect, the prospectus contained therein or any document incorporated by
reference therein includes an untrue statement of a material fact or omits to
state any material fact required to be stated therein or necessary to make the
statements therein not misleading in the light of the circumstances then
existing; or (D) of any request by the Commission for the amending or
supplementing of such registration statement or prospectus or for additional
information;

         (vi) use its reasonable best efforts to furnish, at the request of any
selling holder, on the date that shares of Registrable Stock are delivered to
the underwriters for sale pursuant to such registration statement, if such
securities are being sold through underwriters, or on the date that the
registration statement becomes effective, if such securities are not being sold
through underwriters: (A) an opinion dated such date of counsel representing the
Company for the purposes of such registration, addressed to the underwriters, if
any, and to each such selling holder of Registrable Stock, stating that such
registration statement has become effective under the Securities Act and that
(1) to the knowledge of such counsel, no stop order suspending the effectiveness
thereof has been issued and no proceedings for that purpose have been instituted
or are pending or contemplated under the Securities Act and (2) the registration
statement, the related prospectus, and each amendment or supplement thereof,
comply as to form in all material

                                       12

<PAGE>

respects with the requirements of the Securities Act (except that such counsel
need express no opinion as to financial statements, the notes thereto, and the
financial schedules and other financial and statistical data contained therein),
and (B) a letter dated such date from the independent public accountants
retained by the Company, addressed to the underwriters, if any, and to such
sellers of Registrable Stock stating that they are independent public
accountants within the meaning of the Securities Act and that, in the opinion of
such accountants, the financial statements of the Company included in the
registration statement or the prospectus, or any amendment or supplement
thereof, comply as to form in all material respects with the applicable
accounting requirements of the Securities Act, and such letter shall
additionally cover such other financial matters (including information as to the
period ending no more than five business days prior to the date of such letter)
with respect to the registration in respect of which such letter is being given
as such underwriters or sellers of Registrable Stock may reasonably request; and

         (vii) take such actions as may be necessary or appropriate to cause the
Registrable Stock so to be registered to be listed on the principal securities
exchange (or on the NASDAQ National Market System, as the case may be) on which
shares of Common Stock are then traded.

         In connection with each registration hereunder, the selling holders of
Registrable Stock will furnish to the Company in writing such information with
respect to themselves and the proposed distribution by them as shall be
reasonably necessary in order to assure compliance with federal and applicable
state securities laws.

         (c) Expenses. The Company will pay all Registration Expenses in
             --------
connection with each registration statement filed pursuant to Section 7(a)
hereof. All Selling Expenses in connection with any registration statement filed
pursuant to Section 7(a) hereof shall be borne by the participating holders of
Registrable Stock in proportion to the number of shares proposed to be sold by
each.

         (d) Rule 144 Reporting. The Company agrees with each of the NHR Holders
             ------------------
that (i) the Company shall make and keep public information available, as those
terms are understood and defined in Rule 144 under the Securities Act, at all
times as it is able to do so, (ii) the Company shall file with the Commission in
a timely manner all reports and other documents as the Commission may prescribe
under Section 13(a) or 15(d) of the Exchange Act at any time that the Company is
subject to such reporting requirements of the Exchange Act, (iii) the Company
shall furnish to any holder of Registrable Stock forthwith upon request (1) a
written statement by the Company as to its compliance with the reporting
requirements of Rule 144, and of the Securities Act and the Exchange Act, (2) a
copy of the most recent annual or quarterly report of the Company and (3) such
other reports and documents so filed as such holder may reasonably request to
avail itself of any rule or regulation of the Commission allowing a holder of
Registrable Stock to sell any such securities without registration.

         SECTION 8. Indemnification.
                    ---------------

         (a) In the event of a registration of any of the Registrable Stock
under the Securities Act pursuant to Section 7(a) hereof, the Company will
indemnify and hold harmless,

                                       13

<PAGE>

to the fullest extent permitted by law, each seller of such Registrable Stock
thereunder, each underwriter of Registrable Stock thereunder, each of their
respective affiliates, each of their and their affiliates' respective directors,
officers, fiduciaries, trustees, agents, employees, stockholders, general and
limited partners and members, and each other person, if any, who controls such
seller or underwriter within the meaning of the Securities Act, against any
losses, claims, damages or liabilities, joint or several, actions or proceedings
(whether commenced or threatened) in respect thereof (all of the foregoing,
collectively, "Claims") and expenses (including the reasonable fees and expenses
of counsel, and amounts paid in any settlement effected with the Company's
consent, which consent shall not be unreasonably withheld or delayed) to which
such indemnified party may become subject under the Securities Act or otherwise,
insofar as such Claims or expenses arise out of or are based upon any untrue
statement or alleged untrue statement of any material fact contained in any
registration statement under which such Registrable Stock were registered under
the Securities Act pursuant to Section 7(a), any preliminary prospectus, summary
or final prospectus contained therein, or any amendment or supplement of any
thereof, or any documents incorporated by reference therein, or arise out of or
are based upon the omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, and will reimburse each such indemnified party for any legal or
other expenses reasonably incurred by them in connection with investigating or
defending any such Claim; provided, that the Company will not be liable to any
such indemnified party if and to the extent that any such Claim or expense
arises out of or is based upon an untrue statement or alleged untrue statement
or omission or alleged omission so made in conformity with information
pertaining to such indemnified party furnished by such indemnified party in
writing for use in such registration statement or prospectus.

         (b) In the event of a registration of any of the Registrable Stock
under the Securities Act pursuant to Section 7(a) hereof, each seller of such
Registrable Stock thereunder, severally and not jointly, will indemnify and hold
harmless, to the fullest extent permitted by law, the Company and each person,
if any, who controls the Company within the meaning of the Securities Act, each
officer of the Company who signs the registration statement, each director of
the Company, each underwriter and each person who controls any underwriter
within the meaning of the Securities Act, each other selling stockholder of the
Company under such registration statement and each affiliate, officer, director,
fiduciary, trustee, agent, employee, stockholder, general or limited partner or
member of the Company, each such controlling person, each such officer, each
such director, each such underwriter and each such other selling stockholder
against all Claims and expenses (including reasonable fees and expenses of
counsel, and amounts paid in any settlement effected with the indemnifying
party's consent, which consent shall not be unreasonably withheld or delayed) to
which the Company or such officer or director or underwriter or controlling
person or other selling stockholder may become subject under the Securities Act
or otherwise, insofar as such Claims or expenses arise out of or are based upon
any untrue statement or alleged untrue statement of any material fact contained
in the registration statement under which such Registrable Stock were registered
under the Securities Act pursuant to Section 7(a) any preliminary prospectus,
summary or final prospectus contained therein, or any amendment or supplement of
any thereof, or any documents incorporated by reference therein, or arise out of
or are based upon the omission or alleged omission to state therein a material
fact required to be stated therein or necessary to make the statements therein

                                       14

<PAGE>

not misleading, and will reimburse the Company and each such indemnified party
for any legal or other expenses incurred by them in connection with
investigating or defending any such Claim; provided, that such seller will be
liable hereunder to any such indemnified party if and only to the extent that
any such Claim or expense arises out of or is based upon an untrue statement or
alleged untrue statement or omission or alleged omission made in reliance upon
and in conformity with information pertaining to such seller, as such, furnished
in writing to the Company by such seller for use in such registration statement
or prospectus; provided, further, that the liability of each selling NHR Holder
hereunder shall be limited to the proceeds (net of underwriting discounts and
commissions) received by such seller from the sale of Registrable Stock covered
by such registration statement.

         (c) Promptly after receipt by an indemnified party hereunder of notice
of the commencement of any action, such indemnified party shall, if a claim in
respect thereof is to be made against the indemnifying party hereunder, notify
the indemnifying party in writing thereof, but the omission so to notify the
indemnifying party shall not relieve it from any liability which it may have to
such indemnified party under this Section 8 except to the extent such
indemnifying party is materially prejudiced thereby, and in any event will not
relieve such indemnifying party from any liability which it may have to any
indemnified party other than under this Section 8. In case any such action shall
be brought against any indemnified party and it shall notify the indemnifying
party of the commencement thereof, the indemnifying party shall be entitled to
participate in and, to the extent it shall wish, to assume and undertake the
defense thereof with counsel satisfactory to such indemnified party, and, after
notice from the indemnifying party to such indemnified party of its election so
to assume and undertake the defense thereof, the indemnifying party shall not be
liable to such indemnified party under this Section 8 for any legal expenses
subsequently incurred by such indemnified party in connection with the defense
thereof other than reasonable costs of investigation and of liaison with counsel
so selected; provided, that, if the defendants in any such action include both
             --------
the indemnified party and the indemnifying party and the indemnified party shall
have reasonably concluded that there may be reasonable defenses available to it
which are different from or additional to those available to the indemnifying
party, or if the interests of the indemnified party reasonably may be deemed to
conflict with the interests of the indemnifying party, or if the indemnifying
party shall not diligently continue such defense in good faith, the indemnified
party shall have the right to select a separate counsel and to assume such legal
defenses and otherwise to participate in the defense of such action, with the
expenses and fees of such separate counsel and other expenses related to such
participation to be reimbursed by the indemnifying party as incurred.

         (d) Notwithstanding the foregoing, any indemnified party shall have the
right to retain its own counsel in any such action, but except as set forth
above the fees and disbursements of such counsel shall be at the expense of such
indemnified party unless (i) the indemnifying party shall have failed to retain
counsel for the indemnified person as aforesaid or (ii) the indemnifying party
and such indemnified party shall have mutually agreed to the retention of such
counsel. It is understood that the indemnifying party shall not, in connection
with any action or related actions in the same jurisdiction, be liable for the
fees and disbursements of more than one firm (together with local counsel) to
act as counsel for the indemnified party. The indemnifying party shall not be
liable for any settlement of any proceeding effected without its written consent
(which shall not be unreasonably withheld or

                                       15

<PAGE>

delayed), but if settled with such consent or if there be a final judgment for
the plaintiff, the indemnifying party agrees to indemnify the indemnified party
from and against any loss or liability by reason of such settlement or judgment.
No indemnifying party shall, without the written consent of the indemnified
party (which shall not be unreasonably withheld or delayed), effect the
settlement or compromise of, or consent to the entry of any judgment with
respect to, any pending or threatened action in respect of which indemnification
may be sought hereunder (whether or not the indemnified party is an actual or
potential party to such action) unless such settlement, compromise or judgment
(i) includes an unconditional release of such indemnified party from all
liability arising out of such action and (ii) does not include a statement as to
or an admission of fault, culpability or a failure to act by or on behalf of
such indemnified party.

         (e) If for any reason the indemnification provided for in this Section
8 is unavailable or insufficient to hold harmless an indemnified party under
this Section 8 in respect of any Claims or expenses in respect thereof referred
to therein, then each indemnifying party shall in lieu of indemnifying such
indemnified party contribute to the amount paid or payable by such indemnified
party as a result of such Claims or expenses in such proportion as appropriate
to reflect the relative fault of the parties in connection with the statements
or omissions which resulted in such Claims or expenses as well as any other
relevant equitable considerations, including the failure to give any notice
under Section 8(c). The relative fault shall be determined by reference to,
among other things, whether the untrue or alleged untrue statement of a material
fact relates to information supplied by the indemnifying party, on the one hand,
or the indemnified party, on the other, and to the parties' relative intent,
knowledge, access to information and opportunity to correct or prevent such
statement or omission. The Company and each of you agree that it would not be
just and equitable if contributions pursuant to this paragraph (e) were
determined by pro rata allocation (even if all of the sellers of such
Registrable Stock were treated as one entity for such purpose) or by any other
method of allocation which did not take account of the equitable considerations
referred to above in this paragraph (e). The amount paid or payable by an
indemnified party as a result of the Claims and expenses in respect thereof,
referred to above in this paragraph (e), shall be deemed to include any legal or
other expenses reasonably incurred by such indemnified party in connection with
investigating or defending any such action or claim. Notwithstanding the
provisions of this paragraph (e), no seller of such Registrable Stock or related
indemnified party shall be required to contribute any amount in excess of the
amount of proceeds (net of underwriting discounts and commissions) received by
such seller from the sale of Registrable Stock covered by such registration
statement. No person guilty of fraudulent misrepresentations (within the meaning
of Section 11(f) of the Securities Act), shall be entitled to contribution from
any person who is not guilty of such fraudulent misrepresentation.

         (f) The indemnification of underwriters provided for in this Section 8
shall be on such other terms and conditions as are at the time customary and
reasonably required by such underwriters. In that event the indemnification of
the sellers of Registrable Stock in such underwriting shall at the sellers'
request be modified to conform to such terms and conditions.

         (g) The indemnification and contribution agreements contained herein
shall be in addition to any other rights to indemnification and contribution
which any indemnified party may have pursuant to law or contract or otherwise,
shall remain operative and in full force and

                                       16

<PAGE>

effect regardless of any investigation made or omitted by or on behalf of any
indemnified party and shall survive the transfer of Registrable Stock by any
such party.

         SECTION 9. Representations and Warranties of the Parties. Each of the
                    ---------------------------------------------
parties hereto, severally and not jointly, represents and warrants (as to itself
only) to each of the other parties hereto as follows:

         (a) Each such party that is a corporation, limited liability company,
limited partnership, trust or other entity, is duly organized, validly existing
and in good standing, in each case to the extent applicable, under the laws of
the jurisdiction of its organization. Each such party that is a corporation,
limited liability company, limited partnership, trust or other entity has the
requisite power and authority, and each such party that is an individual has the
capacity, to execute, deliver and perform this Agreement. The execution,
delivery and performance of this Agreement by such party will not violate any
provision of the charter, bylaws or other governing instruments, if any, of such
party, any provision of applicable law, any order of any court or other agency
of government applicable to such party, or any provision of any indenture,
agreement or other instrument to which such party or any of such party's
properties or assets is bound, or conflict with, result in a breach of or
constitute (with due notice or lapse of time or both) a default under any such
indenture, agreement or other instrument.

         (b) This Agreement has been duly executed and delivered by such party,
and when executed by the other parties hereto will constitute the legal, valid
and binding obligation of such party, enforceable against it in accordance with
its terms.

         SECTION 10. Miscellaneous.
                     -------------

         (a) Headings. Headings of sections and paragraphs of this Agreement are
             --------
inserted for convenience of reference only and shall not affect the
interpretation or be deemed to constitute a part hereof.

         (b) Severability. In the event that any one or more of the provisions
             ------------
contained in this Agreement or in any other instrument referred to herein shall,
for any reason, be held to be invalid, illegal or unenforceable, such
illegality, invalidity or unenforceability shall not affect any other provisions
of this Agreement.

         (c) Benefits of Agreement. Nothing expressed by or mentioned in this
             ---------------------
Agreement is intended or shall be construed to give any person other than the
parties hereto and their respective successors and permitted assigns any legal
or equitable right, remedy or claim under or in respect of this Agreement or any
provision herein contained, this Agreement and all conditions and provisions
hereof being intended to be and being for the sole and exclusive benefit of the
parties hereto and their respective successors and permitted assigns.
Notwithstanding anything in this Section 10(c) to the contrary, subject to
compliance with the terms of this Agreement, each NHR Holder shall have the
right to assign its interests hereunder in whole or in part to any transferee of
the Company Shares held by such NHR Holder in compliance with this Agreement.
Except as expressly permitted hereby, each party's rights and obligations under
this

                                       17

<PAGE>

Agreement shall not be subject to assignment or delegation by any party hereto,
and any attempted assignment or delegation in violation hereof shall be null and
void ab initio.

         (d) Notices. Any notice, request, consent or other communications
             -------
required or permitted hereunder shall be deemed to be sufficient and received if
contained in a written instrument delivered in person or by courier or duly sent
by first class certified mail, postage prepaid, or by facsimile addressed to
such party at the address or facsimile number set forth below:

         (1) if to the Company, to it at:

                           5080 Spectrum Drive
                           Suite 400, West Tower
                           Addison, Texas  75001
                           Facsimile Number: (972) 387-1938
                           Attention:  General Counsel

         with a copy to:

                           Reboul, MacMurray, Hewitt, Maynard & Kristol
                           45 Rockefeller Plaza
                           New York, New York  10111
                           Facsimile Number:  (212) 841-5725
                           Attention: Othon A. Prounis, Esq.

         (2) if to any WCAS Holder or NHR Holder, to the address of such
stockholder appearing in Schedule I or Schedule II hereto

         with a copy to:

                  Milbank, Tweed, Hadley & McCloy LLP
                  1 Chase Manhattan Plaza
                  New York, New York 10005
                  Facsimile Number: (212) 530-5219
                  Attention: Robert S. Reder, Esq.

         (3) if to FFT, to it at:

                  Ferrer Freeman Thompson & Co.
                  The Mill
                  10 Glenville Street
                  Greenwich, Connecticut 06831
                  Facsimile Number: (203) 532-8016

         with a copy to:

                                       18

<PAGE>


                  Fried, Frank, Harris, Shriver & Jacobson
                  One New York Plaza
                  New York, New York 10004
                  Facsimile Number: (212) 859-8164
                  Attention: David Golay

or, in any case, at such other address or facsimile number as shall have been
furnished in writing by such party to the other parties hereto. All such
notices, requests, consents and other communications shall be deemed to have
been received (a) in the case of personal or courier delivery, on the date of
such delivery, (b) in the case of mailing by first class certified mail, postage
prepaid, on the fifth business day following the date of such mailing and (c) in
the case of facsimile, when received.

         (e) Entire Agreement; Modification; Termination of Agreement. This
             --------------------------------------------------------
Agreement (including the schedules hereto) constitutes the entire agreement of
the parties with respect to the subject matter hereof and may not be amended,
supplemented or otherwise modified except by an instrument in writing signed by
the Company and (i) a majority in interest of Common Stock held by the WCAS
Holders and (ii) a majority in interest of Common Shares held by the NHR
Holders. Any waiver of any provision of this Agreement must be in a writing
signed by the party against whom enforcement of such waiver is sought.
Notwithstanding anything to the contrary contained in this Agreement, (A) the
provisions of Sections 2(a), 3, 4, 5 and 6 of this Agreement shall terminate
upon the consummation of one or more Public Offerings by the Company of Common
Stock having an aggregate offering price to the public of not less than $100
million and (B) this Agreement shall terminate in its entirety on the tenth
anniversary of the date hereof.

         (f) Covenants Bind Successors and Assigns. All the covenants,
             -------------------------------------
stipulations, promises and agreements in this Agreement contained by or on
behalf of any party shall bind its successors and permitted assigns, whether so
expressed or not.

         (g) Effectiveness. This Agreement shall be of no force or effect unless
             -------------
and until the consummation of the Merger at the Effective Time; upon such
consummation, this Agreement shall be in full force and effect.

         (h) Counterparts. This Agreement may be executed in any number of
             ------------
counterparts, and each such counterpart hereof shall be deemed to be an original
instrument, but all such counterparts together shall constitute but one
agreement.

         (i) Changes in Company Capital Stock. If, and as often as, there are
             --------------------------------
any changes in the Company Capital Stock by way of stock split, stock dividend,
combination or reclassification, or through merger, consolidation,
reorganization or recapitalization, or by any other means, appropriate
adjustment shall be made in the provisions hereof as may be required so that the
rights and privileges granted hereby shall continue with respect to the Company
Shares.

         (j) Specific Performance. Each party hereto agrees that a remedy at law
             --------------------
for any breach or threatened breach by such party of this Agreement would be
inadequate and therefore

                                       19

<PAGE>

agrees that any other party hereto shall be entitled to pursue specific
performance of this Agreement in addition to any other available rights and
remedies in case of any such breach or threatened breach.

         (k) Construction. The language used in this Agreement will be deemed to
             ------------
be the language chosen by the parties to express their mutual intent, and no
rule of strict construction will be applied against any party. Unless the
context otherwise requires: (i) words in the singular include the plural, and in
the plural include the singular and (ii) the words "hereof", "herein", and
                                                    ------    ------
"hereunder" and words of similar import when used in this Agreement refer to
 --------
this Agreement as a whole and not to any particular provision of this Agreement,
and section references are to this Agreement unless otherwise specified.

         (l) Governing Law. This Agreement shall be governed by, enforceable
             -------------
under, and construed in accordance with the laws of the State of New York.

         (m) Waiver of Jury Trial. Each of the parties hereto hereby irrevocably
             --------------------
waives any and all right to trial by jury in any legal proceeding arising out of
or related to this Agreement or the transactions contemplated hereby.

         (n) Termination of NHR Stockholders Agreement. The parties hereto agree
             -----------------------------------------
that, upon the effectiveness of this Agreement, the Amended and Restated
Stockholders Agreement dated as of July 3, 1996 by and among NHR and its
stockholders, as amended, shall be terminated and of no further force and
effect.

                            [SIGNATURE PAGES FOLLOW]

                                       20

<PAGE>

         IN WITNESS WHEREOF, each of the parties hereto has duly executed this
Agreement as of the day and year first above written.

                                       The Company:
                                       -----------

                                       CONCENTRA INC.


                                       By:______________________________________
                                          Name:
                                          Title:


<PAGE>


                                       The WCAS Holders:
                                       ----------------

                                       WELSH, CARSON, ANDERSON & STOWE VIII,
                                       L.P.

                                       BY: WCAS VIII Associates, L.L.C.,
                                           Its General Partner

                                       By:______________________________________
                                          Managing Member

                                       WCAS HEALTHCARE PARTNERS, L.P.

                                       BY: WCAS HC Partners,
                                           its General Partner

                                       By:______________________________________
                                          General Partner

                                       Patrick J. Welsh
                                       Russell L. Carson
                                       Bruce K. Anderson
                                       Andrew M. Paul
                                       Thomas E. McInerney
                                       Robert A. Minicucci
                                       Anthony J. deNicola
                                       Paul B. Queally
                                       Lawrence B. Sorrel
                                       D. Scott Mackesy
                                       Priscilla A. Newman
                                       Laura M. VanBuren
                                       Sean M. Traynor
                                       John Almedia, Jr.
                                       Jonathan M. Rather


                                       By: /s/ JONATHAN M. RATHER
                                           -------------------------------------
                                       Jonathan M. Rather, Individually and
                                       as Attorney-in-Fact

                                       WCAS MANAGEMENT CORP


                                       By:______________________________________
                                          Title:


<PAGE>


Accepted and agreed to solely for purposes of Section 6 above as of the date
first above written:

FERRER FREEMAN THOMPSON & CO., LLC

on behalf of FFT PARTNERS I, L.P.
and as its General Partner

and

on behalf of FFT EXECUTIVE
PARTNERS I, L.P. and as its General Partner


and

on behalf of FFT PARTNERS II, L.P.
and as its General Partner


By:_____________________________________
   Name:
   Title:


<PAGE>


               STOCKHOLDERS AGREEMENT - NHR HOLDER SIGNATURE PAGE


                                       NHR Holder:
                                       ----------


                                       By:______________________________________
                                          Name:
                                          Title:


<PAGE>


                                                                      SCHEDULE I
                                                                      ----------

                                  WCAS Holders
                                  ------------


WELSH, CARSON, ANDERSON & STOWE VIII, L.P.
WCAS HEALTHCARE PARTNERS, L.P.
WCAS MANAGEMENT CORP
Patrick J. Welsh
Russell L. Carson
Bruce K. Anderson
Andrew M. Paul
Thomas E. McInerney
Robert A. Minicucci
Anthony J. deNicola
Paul B. Queally
Lawrence B. Sorrel
D. Scott Mackesy
Priscilla A. Newman
Laura M. VanBuren
Sean M. Traynor
John Almedia, Jr.
Jonathan M. Rather

c/o   Welsh, Carson, Anderson & Stowe
      320 Park Avenue, Suite 2500
      New York, New York 10022
      Attention: Paul B. Queally
      Facsimile:  (212) 893-9566


<PAGE>


                                                                     SCHEDULE II
                                                                     -----------

                                  NHR Holders1
                                  ------------


         Name                           Address For Notices
         ----                           -------------------


                                    [TO COME]


-----------------------
1 Will include all NHR stockholders other than WCAS persons.