<PAGE>   1

                                                                   EXHIBIT 10.19


                            AGREEMENT OF SUBSUBLEASE

                                     between

                          AMERIQUEST TECHNOLOGIES, INC.
                                 Subsublandlord


                                       and


                         SYNDICATED OFFICE SYSTEMS, INC.
                                       and
                          TENET HEALTHCARE CORPORATION
                                formerly known as
                       National Medical Enterprises, Inc.
                                  Subsubtenant

                                    Premises:

                                  A portion of
                                 MACARTHUR PLACE
                              3 Imperial Promenade
                              Santa Ana, California

<PAGE>   2



             
<TABLE>
<S>                                                                                            <C>
1.     Subsubleasing of Premises................................................................1

2.     Term.....................................................................................1

3.     Cancellation Rights......................................................................3

4.     Rents....................................................................................3

5.     Condition of the Premises................................................................5

6.     Incorporation of the Master Lease........................................................5

7.     Covenant of Quiet Enjoyment..............................................................9

8.     Assignment and Undersubletting...........................................................9

9.     Alterations.............................................................................10

10.    Notices.................................................................................11

11.    Parking.................................................................................11

12.    Signage.................................................................................12

13.    Master Landlord's Consent...............................................................12

14.    Miscellaneous...........................................................................13

15.    Participation Agreement; Agreement Regarding Engineering and
       Construction Services...................................................................14

16.    Binding Effect..........................................................................15
</TABLE>


<PAGE>   3



                                   EXHIBIT A3



<PAGE>   4


       THIS AGREEMENT OF SUBSUBLEASE (this "Subsublease") is made as of the 18th
day of January, 1996, between AMERIQUEST TECHNOLOGIES, INC., a Delaware
corporation presently having an office address at 3 Imperial Promenade, Suite
300, Santa Ana, California ("Subsublandlord") and Syndicated Office Systems,
Inc., and Tenet Healthcare Corporation, formerly known as National Medical
Enterprises, Inc. a Delaware corporation, presently having an office at 3
Imperial Promenade, Suite 1100, Santa Ana, California (collectively,
"Subsubtenant").

                              W I T N E S S E T H:

       WHEREAS Brookfield Imperial, Inc., a California corporation is the
successor in interest to BCE Development Inc. ("Master Landlord") under that
certain lease dated June 27, 1989, as amended by amendments thereto dated
October 24, 1991 and September 23, 1992 (as so and hereafter amended, the
"Master Lease") and subsequently subleased to AmeriQuest Technologies, Inc., by
the Austin Company ("Sublandlord") dated December 5, 1994, demised portions (the
"Premises") of the building known as 3 Imperial Promenade, Suites 200 which
consists of 28,317 rentable square feet and 300 which consists of 26,663
rentable square feet, 3 Imperial Promenade, Santa Ana, California (the
"Building"). (All capitalized terms not otherwise defined herein shall have the
meaning given them in the Master Lease.) The Premises is depicted as "Exhibit
A1" for Suite 200 and "Exhibit A2" for Suite 300.

       WHEREAS Subsublandlord desires to subsublease to Subsubtenant, and
Subsubtenant desires to subsublease from Subsublandlord, the Premises on the
terms and conditions contained herein.

       NOW, THEREFORE, in consideration of the mutual covenants herein
contained, it is mutually agreed as follows:


       1.     Subsubleasing of Premises.

       Subsublandlord hereby subsubleases to Subsubtenant, and Subsubtenant
hereby hires from Subsublandlord, all of the Premises.


       2.     Term.

       The term of this Subsublease shall commence on May 1, 1996, for Suite 200
and March 1, 1997 for Suite 300 (the "Commencement Date") and shall end on March
31, 2006 or on such earlier date upon which such term shall expire or be
terminated pursuant to any of the conditions or covenants of this Subsublease or
pursuant to law; provided, however, that if Subsublandlord is unable to deliver
possession of the Premises to Subsubtenant on the Commencement Date set forth
above because, either Sublandlord or the Master Landlord has not consented to
this Subsublease, Subsublandlord shall not be subject to any liability for its
failure to give possession and the validity of this Subsublease shall not be
impaired, nor shall the same be construed 


                                       1
<PAGE>   5

to extend the term of this Subsublease, and the Commencement Date shall be that
date after receipt by Subsublandlord of the Master Landlord's consent and
delivery of possession of the Premises to Subsubtenant. Notwithstanding the
foregoing, Subsublandlord shall use its best reasonable efforts to vacate Suite
200 by March 15, 1996 so Subsubtenant shall have the right to early access to
Suite 200 for tenant improvements, wiring, set-up and testing forty five (45)
days prior to the Commencement Date. During the forty five (45) day period,
Subsubtenant shall install partitions, which are mutually acceptable to
Subsubtenant and Subsublandlord, (consent by Subsublandlord shall not be
unreasonably withheld) at the top and bottom of the common stairway connecting
the third floor reception area with the second floor. The costs of the
partitions shall be reasonable, and shared equally by Subsublandlord and
Subsubtenant. Subsubtenant and Subsublandlord will work toward a mutually
satisfactory schedule which has been agreed to be March 15, 1996 so to allow
Subsublandlord reasonable time to relocate out of Suite 200 and allow
Subsubtenant to do the proposed tenant improvement work. In addition,
Subsublandlord shall use its best reasonable efforts to vacate Suite 300 so
Subsubtenant shall have the right to early access to Suite 300 for tenant
improvements, wiring, set-up and testing thirty (30) days prior to the
Commencement Date, which shall be January 29th, 1997.

       In order to accommodate Subsubtenant's special needs, prior to the
Commencement Date Subsublandlord shall use its reasonable best efforts to make
portions of the Premises available for the installation of tenant Improvements
provided Subsubtenant complies with Section 9.2 below.

       Subsublandlord will continue to have reasonable access and use of the
existing computer room in Suite 200 until Subsubtenant occupies Suite 300. There
will be no charge to Subsublandlord for the use of the computer room, which use
shall cease 30 days prior to Subsubtenant occupying Suite 300. Subsublandlord
shall provide keypad access at the computer room door, stairwell and at each end
of the corridor which accesses the computer room. If the proposed keypad system
does not meet City of Santa Ana codes, then Subsublandlord and Subsubtenant
shall work toward a mutually agreeable solution. Should Subsublandlord no longer
use the computer room primarily for computer purposes, then Subsubtenant shall
assume the space. The computer room is outlined and indicated as "Exhibit A3".
Subsubtenant reserves the right to access the computer room with prior
reasonable notice to Subsublandlord for assessing Subsubtenant future
improvements.

       Subsublandlord and Subsubtenant covenant and agree that while
Subsublandlord maintains and operates its computer room on the Second (2nd)
Floor, Subsublandlord shall comply with the insurance provisions of Section 22
of the Master Lease as if Subsublandlord were the Tenant under the Master Lease
and shall (1) name Subsubtenants as an additional insured but only with respect
to liability arising out of Subsublandlord's use, operation and occupancy of the
computer room, (2) contain a cross-liability provision for Subsubtenant's
benefit, and (3) contain a provision that the insurance provided by
Subsublandlord under Section 22 of the Master Lease shall be primary and
non-contributing with any other insurance available to Subsubtenant. Further,
Subsublandlord shall provide a business interruption and loss of income policy


                                       2

<PAGE>   6

for the sole and exclusive benefit of Subsubtenant, during all periods in which
Subsublandlord occupies the 2nd floor computer room. With respect to the space
occupied by Subsubtenant under this Subsublease, Subsubtenant shall comply with
Section 22 of the Master Lease as though Subsubtenant were the Tenant under the
Master Lease.


       3.     Cancellation Rights.

              Provided Subsubtenant is not then in breach of this Subsublease,
Subsubtenant may elect to terminate this Subsublease on September 30, 2000 by
delivering written notice of that intent to terminate ("Termination Notice") to
Subsublandlord on or before September 30, 1999. The Termination Notice shall
only be effective if, concurrently with the Termination Notice, Tenant pays
Subsublandlord $1,100,000.00 ("Termination Payment"). The Termination Payment
shall be in addition to and not in lieu of the Fixed Rent and all other payments
(except payments for damages under Paragraph 25(c) of the Master Lease)
Subsubtenant is obligated to pay under the Subsublease during the period up to
September 30, 2000; provided, however, that on the date the Subsublease
terminates under this paragraph, Subsubtenant shall be released from
Subsubtenant's obligations to pay Fixed Rent, Additional Rent, or other rent
which arise under this Subsublease subsequent to that date (other than
obligations under indemnity provisions). Nothing contained in this paragraph
shall be construed to release Subsubtenant from any of its obligations which
arise under this Subsublease upon the termination of the Subsublease or the
expiration of the Term, including without limitation those tenant obligations
which arise under Paragraphs 14 and 33 of the Master Lease.



       4.     Rents.

              4.1 Subsubtenant shall pay to Subsublandlord Fixed Rent at the
rate of $1.55 per square foot of the Premises per month which amount is
$43,891.35 for Suite 200 and $41,327.65 for Suite 300 ("Fixed Rent"), with the
first full month's Fixed Rent for suite 200 only payable upon execution of this
Subsublease with the first full month's Fixed Rent for suite 300 only upon
occupancy and with each subsequent month's Fixed Rent payable on the first day
of each month following the Commencement Date; provided, however, that if the
Commencement Date is other than the first day of a month (a) the first payment
due shall be calculated on a pro-rata basis considering the portion of the month
falling on or after the Commencement Date and (b) the payment due on the first
day of any month in which shall occur any anniversary of the Commencement Date
shall be calculated on a pro-rata basis considering the rate of fixed rent
applicable to each portion of such month. Subsublandlord shall abate the Fixed
Rent payments due for months two (2) through eight and one half (8 1/2) of this
Subsublease for Suite 200 and Suite 300, respectively, provided that
Subsubtenant is not in default with respect to any of its obligations under this
Subsublease at the 

                                       3

<PAGE>   7

commencement of any such month. The square footage of the Premises shall be as
calculated by the Master Landlord under the Master Lease.

              4.2 In addition to the Fixed Rent, Subsubtenant shall pay monthly
commencing in January, 1997 for Suite 200 and January 1998 for Suite 300 all
incremental expenses referred to in the Master Lease as "Operating Expenses" in
excess of those amounts calculated for calendar year 1996, based on the
assumption that such 1996 Operating Expenses will be the base year for Suite 200
and on the assumption that such 1997 Operating Expenses will be the base year
for Suite 300. Operating Expenses are based on the higher of (i) a ninety-five
percent (95%) occupancy rate, or (ii) the actual occupancy rate. The intent of
the parties under this provision is that Subsublandlord shall be responsible
during the Term hereof for the proportionate share of Operating Expenses each
year of the Term up to but not in excess of the annual obligation therefor
relating to calendar year 1996 for Suite 200 and calendar year 1997 for Suite
300.

              4.3 As used herein the term "Additional Rent" shall refer to all
sums of money which shall become due from and payable by Subsubtenant to
Subsublandlord hereunder, other than Fixed Rent, and the term "Rents" shall
refer to Fixed Rent and Additional Rent. All Rents shall be payable in lawful
money of the United States at such place and to such person as Subsublandlord
shall from time to time designate.

              4.4 Subsubtenant shall promptly pay all Rents as and when the same
shall become due and payable without set-off, offset or deduction of any kind
whatsoever except as otherwise provided for herein and, in the event of
Subsubtenant's failure to pay any Additional Rent when due, Subsublandlord shall
have all of the rights and remedies provided for herein or at law or in equity
in the case of non-payment of Fixed Rent.

              4.5 Subsublandlord's failure during the term of this Subsublease
to prepare and deliver any statements or bills required or permitted to be
delivered to Subsubtenant hereunder, or Subsublandlord's failure to make a
demand under this Subsublease, shall not in any way be deemed to be a waiver of,
or cause Subsublandlord to forfeit or surrender, its rights to collect any rents
which may have become due pursuant to this subsublease during the term hereof.
Subsubtenant's liability for rents accruing during the term of this Subsublease
shall survive the expiration or sooner termination of this Subsublease.

              4.6 Subsubtenant shall have the right, subject to obtaining all
reviews, approvals and consents required by the Master Lease, to perform certain
Subsubtenant improvements to the Premises such as partitioning, doors, floor
coverings (the "Subsubtenant Improvements"). Subsublandlord shall provide
subsubtenant a tenant improvement allowance of $6.00 per rentable square foot
for the Premises subsubleased by Subsubtenant, paid by Subsublandlord to
Subsubtenant within 30 days of Subsubtenant's occupancy of Suite 200 and Suite
300, respectively.


                                       4

<PAGE>   8

       5.     Condition of the Premises.

              Subsubtenant represents that it has examined (or waived
examination of) the Premises. Subsublandlord has not made and does not make any
representations or warranties as to the physical condition of the Premises
(including any latent defects in or to the Premises), the uses to which the
Premises may be put, or any other matter or thing affecting or relating to the
Premises, except as specifically set forth in this Subsublease. Subsubtenant
agrees to accept the Premises in their "as is" condition as of the date hereof
as the same may be affected by reasonable wear and tear after the date hereof,
and (b) Subsublandlord shall have no obligation whatsoever to alter, improve,
decorate or otherwise prepare the Premises for Subsubtenant's occupancy.
However, notwithstanding the above, Subsublandlord shall use best effort to
remove all furniture, personal fixtures and trash from the Premises upon
vacating the Premises.


       6.     Incorporation of the Master Lease and Sublease.

              6.1 Subsublandlord represents that a true and complete copy of the
Master Lease and Sublease is attached hereto as Exhibit B. Subsublandlord shall
not voluntarily surrender the Master Lease and Sublease or amend the same in a
manner adverse to Subsubtenant. If the Master Lease and Sublease shall terminate
for any reason then this Subsublease shall also terminate without liability of
either party to the other on account thereof; provided, however, that if such
termination of the Master Lease and Sublease shall have arisen out of

                   (a) any default by Subsublandlord as subtenant thereunder not
arising out of any default by Subsubtenant as Subsubtenant hereunder, or

                   (b) a voluntary surrender by Subsublandlord in violation of
the preceding sentence, then such termination shall be deemed to be a violation
of Section 7 hereof and Subsublandlord shall be liable to Subsubtenant to the
extent provided by applicable law on account thereof. This Subsublease is
expressly subject to all of the obligations of Subsublandlord as Subtenant under
the Master Lease.

              6.2 Except as otherwise expressly provided in, or otherwise
inconsistent with, this Subsublease, the provisions of the Master Lease listed
below (the "Incorporated Provisions") are hereby incorporated in this
Subsublease by reference with the same force and effect as if set forth at
length herein, except that unless the context requires otherwise,

                   (i) references in such provisions to Landlord shall be deemed
to refer to Subsublandlord,

                   (ii) references in such provisions to Tenant shall be deemed
to refer to Subsubtenant,


                                       5

<PAGE>   9

                   (iii) references in such provisions to the Premises or the
Demised Premises shall be deemed to refer to the Premises hereunder,

                   (iv) references in such provisions to other Incorporated
Provisions shall be deemed to refer to such Incorporated Provisions as
incorporated herein,

                   (v) references in such provisions to superior lease shall be
deemed to refer to leases to which the Master Lease is subordinate and
references in such provisions to superior mortgages shall refer to mortgages to
which the Master Lease is subordinate,

                   (vi) references in such provisions to subleases, subletting,
or subtenants shall be deemed to refer to undersubsubleases, undersubsubletting,
and undersubsubtenants,

                   (vii) whenever, pursuant to any of the Incorporated
Provisions as incorporated herein, Subsubtenant is required to furnish
insurance, indemnification or other similar protection to or for Subsublandlord,
or to take some act as designated or directed by Subsublandlord or to the
satisfaction of Subsublandlord, Subsubtenant shall be required to furnish the
same to or for Sublandlord, Master Landlord and Subsublandlord, or to take the
same as designated or directed by Master Landlord, Sublandlord, or
Subsublandlord or to the satisfaction of Master Landlord, Sublandlord or
Subsublandlord,

                   (viii) whenever, pursuant to any of the Incorporated
Provisions as incorporated herein, Subsubtenant is required to obtain the
consent or approval of Subsublandlord to or with respect to any act, omission or
thing (e.g. to any under subsublease or assignment or to the making of any
alterations, installations, additions or improvements), Subsubtenant shall be
required to obtain the consent or approval of Master Landlord, Sublandlord and
Subsublandlord to or with respect to such act, omission or thing. Additionally,
any such consent by Sublandlord and Subsublandlord shall not unreasonably be
withheld or delayed.

                   (ix) whenever, pursuant to any of the Incorporated Provisions
as incorporated herein, Subsubtenant grants any release, waiver or similar thing
to Subsublandlord, Subsubtenant shall be deemed to have granted the same to
Master Landlord and Sublandlord,

                   (x) whenever, pursuant to any of the Incorporated Provisions
as incorporated herein, Subsubtenant grants Subsublandlord any right of entry,
access or use of the Premises, Subsubtenant shall be deemed to have granted such
right to Master Landlord and Sublandlord,

                   (xi) time periods provided for in the Incorporated Provisions
shall be shortened or lengthened, as the case may be, as necessary so that
actions or omissions relating thereto may be coordinated with the corresponding
actions or omissions under the Master Lease or performed within the time
required by the Master Lease.

                                       6
<PAGE>   10

The Incorporated Provisions of the Master Lease are all of the provisions
thereof except for Sections 56 and 57 rights to which are reserved by
Sublandlord.

              6.3 Notwithstanding anything to the contrary contained in this
Subsublease (including any of the Incorporated Provisions as herein
incorporated), Subsublandlord shall not be obligated

                   (i) to provide any of the services that Master Landlord has
agreed to in the Master Lease to provide or is required by law to provide, or

                   (ii) to make any of the repairs or restorations that Master
Landlord has agreed in the Master Lease to make or is required by law to make,
or

                   (iii) to comply with any laws or requirements of public
authorities, or

                   (iv) to take or to refrain from taking any other action that
Master Landlord has agreed in the Master Lease to take or to refrain from taking
or is required by law to take or to refrain from taking (including, in either
case, any obligations with respect to giving consents, approvals, etc.), or

                   (v) to perform any obligation that Master Landlord has agreed
in the Master Lease to perform, and Subsublandlord shall have no liability to
Subsubtenant on account of any failure of Master Landlord (or Sublandlord) to
provide, make, comply with, take, refrain from taking, or perform any of the
foregoing. With reference to the foregoing, Subsublandlord agrees:

                      (a) upon Subsubtenant's request, to use reasonable 
efforts, at Subsubtenant's expense (such expense to be prepaid by Subsubtenant
prior to Subsublandlord commencing or continuing to act under this clause (a)),
to (x) compel Master Landlord to provide, make, comply, take, refrain from
taking or perform the same or (y) recover damages on account of Master
Landlord's failure to do so, including within such reasonable efforts the
commencement and prosecution, at Subsubtenant's expense, of an action at law or
in equity, and

                      (b) that, if any right or remedy of Subsublandlord or any
duty or obligation of Master Landlord or Sublandlord in any case under any of
the Incorporated Provisions is subject to or conditioned upon Subsublandlord's
making any demand upon Master Landlord or giving any notice, request or
statement to Master Landlord or taking any other action then, if Subsubtenant
shall so request, Subsublandlord, at Subsubtenant's expense (such expense to be
prepaid by Subsubtenant prior to Subsublandlord commencing or continuing to act
under this clause (b)), shall make such demand, give such notice, request or
statement or take such other act.

Subsubtenant shall defend, indemnify and hold harmless Subsublandlord from and
against any and all loss, cost, damage and expense incurred by Subsublandlord
under or in connection with (1) any such efforts and/or such action, proceeding,
or arbitration 

                                       7
<PAGE>   11

including reasonable attorneys fees, pursuant to clause (a) above, or (2) any
such demand, notice, request, statement or act, pursuant to clause (b) above.

              6.4 Whenever Subsubtenant desires to do any act or thing which
requires the consent or approval of Subsublandlord under any of the Incorporated
Provisions as incorporated herein:

                  (a) Subsubtenant shall not do such act or thing without first
having obtained the consent or approval of Master Landlord, Sublandlord and
Subsublandlord;

                  (b) Subsublandlord's right to withhold consent or approval
shall be independent of Master Landlord's right. However, such consent shall not
unreasonably be withheld or delayed; and

                  (c) without limiting Subsublandlord's right to withhold
consent or approval in any instance and notwithstanding any Incorporated
Provisions or provision of law requiring Subsublandlord to act reasonably,
Subsublandlord shall be entitled, without liability to Subsubtenant on account
thereof, to withhold consent or approval whenever and for so long as Master
Landlord and/or Sublandlord shall withhold its consent or approval, regardless
of whether or not Master Landlord and/or Sublandlord is entitled to withhold
such consent or approval and regardless of whether Master Landlord and/or
Sublandlord may have liability to Subsublandlord or Subsubtenant on account
thereof; and

                  (d) Subsubtenant shall not request Master Landlord's consent
or approval or the consent or approval of Sublandlord directly; unless
Subsublandlord shall have determined to withhold its consent or approval, the
provisions of Section 6.3 above shall be applicable to the obtaining of Master
Landlord's consent or approval; neither Subsublandlord's forwarding
Subsubtenant's request to Master Landlord and/or Sublandlord nor
Subsublandlord's other efforts to obtain Master Landlord's or Sublandlord's
consent or approval shall constitute Subsublandlord's consent or approval, and
the same shall be without prejudice to Subsublandlord's right to withhold
consent or approval.

              6.5 Notwithstanding any other provision of this Subsublease,
Subsubtenant shall perform all of its obligations hereunder at such time, by
such dates or within such periods as shall be required to avoid any default
under the Master Lease from continuing beyond the period for notice and grace
provided for in the Master Lease; provided, however, that in no event shall this
Section 6.5 extend the time, date or period by or within which Subsubtenant is
required to perform.

              6.6 Subsubtenant shall indemnify Subsublandlord from any loss,
cost, damage or expense (including reasonable attorneys fees) arising out of any
failure by Subsubtenant to perform any of its obligations under this
Subsublease, including any loss, cost, damage or expense which may result from
any default under or termination of the Master Lease arising by reason of any
such failure.


                                       8
<PAGE>   12


       7.     Covenant of Quiet Enjoyment.

              So long as Subsubtenant pays all of the Fixed Rent and Additional
Rent hereunder, and performs all of Subsubtenant's other obligations hereunder,
Subsubtenant shall peaceably and quietly have, hold and enjoy the Premises
subject, nevertheless, to the obligations of this Subsublease and to the Master
Lease, and to any leases, mortgages and other rights and encumbrances superior
in priority to this Subsublease.


       8.     Assignment and Undersubsubletting.

              8.1  Except as provided by and in accordance with the procedure
set forth in Section 26 of the Incorporated Provisions as incorporated herein;

                  (a) this Subsublease shall not be assigned, encumbered or
otherwise transferred;

                  (b) the Premises shall not be undersubsublet by Subsubtenant
in whole or in part, and

                  (c) the Premises shall not be suffered or permitted to be used
or occupied by any person other than Subsubtenant, or an affiliate of
Subsubtenant in whole or in part, without the prior written consent of Master
Landlord, Sublandlord and Subsublandlord in each instance. Any such consent,
assignment, encumbrance or other transfer, and any such undersubsublease, use or
occupancy shall be subject to all of the Incorporated Provisions.

                  (1) Subsublandlord's right to withhold consent or approval
shall be independent of Master Landlord's and Sublandlord's right and, without
limiting Subsublandlord's right to withhold consent or approval for any other
reason, it is specifically agreed that (i) when requesting Subsublandlord's
consent, Subsubtenant shall, with the exception of an affiliate of
Subsubtenants, submit detailed financial information regarding the proposed
assignee or undersubsubtenant, and (ii) Subsublandlord may reasonably withhold
consent or approval if Subsublandlord is not satisfied with the financial
strength of the proposed assignee or undersubsubtenant;

                  (2) without limiting Subsublandlord's right to withhold
consent or approval in any instance or notwithstanding any Incorporated
Provision or provision of law requiring Subsublandlord to act reasonably,
Subsublandlord shall be entitled, without liability to Subsubtenant on account
thereof, to withhold consent or approval whenever and for so long as Master
Landlord or Sublandlord shall withhold its consent or approval, regardless of
whether or not Master Landlord or Sublandlord is entitled to withhold such
consent or approval and regardless of whether Master Landlord or Sublandlord may
have liability to Subsublandlord or Subsubtenant on account thereof; and



                                       9
<PAGE>   13

                  (3) Subsubtenant shall not request Master Landlord's consent
or approval or Sublandlord's consent or approval directly; unless Subsublandlord
shall have determined to withhold its consent or approval, the provisions of
Section 6.3 above shall be applicable to the obtaining of Master Landlord's
consent or approval; neither Subsublandlord's forwarding Subsubtenant's request
to Master Landlord or Sublandlord nor Subsublandlord's other efforts to obtain
Master Landlord's consent or approval shall constitute Subsublandlord's consent
or approval, and the same shall be without prejudice to Subsublandlord's right
to withhold consent or approval; unless Subsublandlord shall have determined to
withhold its consent or approval, the provisions of Section 6.3 above shall be
applicable to the obtaining of Master Landlord's consent or approval.

              8.2 Any undersubsublease shall be subject and subordinate to this
Subsublease. No assignment shall be valid or effective unless and until the
assignee shall have delivered to Subsublandlord an instrument, in form
reasonably satisfactory to Subsublandlord, pursuant to which the assignee
assumes the due observance and performance of all of the obligations of
Subsubtenant hereunder.

              8.3 No assignment or undersubsublease shall release the
Subsubtenant named herein or any of its successors from any liability hereunder.
If this Subsublease is assigned or the Premises or any part thereof are
undersubsublet in violation of this Subsublease, Subsublandlord may collect
rents from or accept performance from the assignee or undersubsubtenant and no
such collection or acceptance shall effect any such release.



       9.     Alterations.

              9.1 Notwithstanding the incorporation herein of Section 14 of the
Master Lease, except as provided in this Section 9.1, Subsublandlord shall not
have the right to require Subsubtenant to remove alterations, installations,
additions or improvements from the Premises; provided, however, that
Subsubtenant shall be required to remove from the Premises any of such items
made or installed by it which, pursuant to the Master Lease, Sublandlord and/or
Subsublandlord is required to remove. Subsublandlord shall forward to
Subsubtenant any notice received from Master Landlord requiring removal of any
of such items and any such notice shall be binding on Subsubtenant, regardless
of when received by it. Subsubtenant's removal obligations pursuant to this
Section 9.1 shall also include all related restoration as required by Sections
13 and 14 of the Master Lease or any other applicable provision thereof.



                                       10

<PAGE>   14


              9.2 Subsubtenant shall, with the exception of minor modifications,
(such as, the installation of pictures, voice/data cable, etc.), not commence or
prosecute any alterations, installation, addition or improvements unless, in
addition to having complied with all other provisions of this Subsublease and
the Incorporated Provisions as incorporated herein, Subsubtenant shall have
furnished to Subsublandlord (a) a fixed price general contract covering the
same, and (b) payment and performance bonds in favor of Subsublandlord,
Subsublandlord and the Master Landlord guaranteeing lien free completion of the
work in form, amount and issued by a surety satisfactory to Subsublandlord in
its reasonable judgment. Additionally, consent by Sublandlord, and
Subsublandlord shall not unreasonably be withheld or delayed.



       10.    Notices.

              Any notice, statement, demand, consent, approval, advice or other
communication required or permitted to be given, rendered or made by either
party to the other, pursuant to this Sublease or pursuant to any applicable law
or requirement of public authority (collectively, "Notice") shall be in writing
and shall be deemed to have been properly given, rendered or made only if sent
by personal delivery, receipted by the party to whom addressed, or by registered
or certified mail, return receipt requested, posted in a United States post
office station or depository in the continental United States, addressed

                  (i) to Subsubtenant at its address first above written,
Attention: Mr. Arnold Robin, President , Syndicated Office Systems, 3 Imperial
Promenade, Suite 1100, Santa Ana, California 92707,

                  (ii) to Subsublandlord, Attention: Mr. Mark Malford, Chief
Operating Officer, AmeriQuest Technologies, Inc., 3 Imperial Promenade, Suite
300, Santa Ana, California 92707.

Either party may, by Notice actually received, designate (i) a different address
in the United States for Notices intended for it, and (ii) require the other
party to provide a copy of any Notices to any other person at any other address
in the United States.



       11.    Parking.

              Subject to the provisions of Section 40 of the Master Lease
pertaining to the parking rights granted to Subsublandlord, Subsubtenant shall
have the right to utilize all of the parking spaces allocated to Subsublandlord
under Section 1(k) of the Master Lease (the "Allocated Spaces"), and
Subsublandlord shall transfer to Subsubtenant on or prior to the Commencement
Date the proportionate share of parking cards for Suite 200, which shall include
13 reserved parking spaces, identified as numbers 67 through 73 inclusive, and
49 through 54, until Subsubtenant's occupancy of Suite 300 then all of the
parking cards, which shall include 12 reserved parking spaces, identified as



                                       11

<PAGE>   15

number 55 through 66, inclusive, shall be transferred and/or any other access
devices for the same to the extent provided to Subsublandlord by Master
Landlord.

              Notwithstanding any provisions to the contrary herein or in the
Master Lease, Subsubtenant shall have the right to use the Allocated Spaces free
of any additional charge until March 31, 2000. Thereafter, Subsubtenant shall
pay to Subsublandlord, on a monthly basis, as Additional Rent, $25 per space for
the balance of the Term of this Subsublease. Nothing contained in the Paragraph
11 shall be construed as Master Landlord's agreement to provide any parking to
Sublandlord, Subsublandlord, or Subsubtenant free of charge or at a discount.


       12.    Signage.

              Subsubtenant shall be entitled to Subsublandlord's signage rights
as set forth in Section 55 of the Master Lease, subject to the review and
approval of such signage by the Master Landlord and the City of Santa Ana. The
cost of removal of the existing signage, together with the costs of all
Subsubtenant's signage and installation, maintenance and ultimate removal
thereof shall be at Subsubtenant's sole expense. In addition, Subsubtenant shall
have the right to the top name on the monument sign on the corner of Imperial
Promenade and Regency Boulevard.


       13.     Master Landlord's and Sublandlord's Consent.

               As an inducement to the Master Landlord and Sublandlord to
consent to this Subsublease, and as required by Section 26(d) of the Master
Lease, Subsublandlord and Subsubtenant each agree as follows:

               (a) This Subsublease shall be subject and subordinate to the
Master Lease and the Sublease and to all mortgages recorded against the Building
and underlying land prior to the date hereof;

               (b) Master Landlord and Sublandlord may enforce the provisions of
this Subsublease, including the collection of rent;

               (c) In the event of termination of the Master Lease for any
reason, including without limitation, a voluntary surrender by Sublandlord or
Subsublandlord, or in the event of any re-entry or repossession of the Premises
by Master Landlord, Master Landlord may, at its option, either

                    (i)    terminate the Subsublease or;

                    (ii) take over all of the right, title and interest of
Subsublandlord, as subsublessor, under this Subsublease, in which case
Subsubtenant shall attorn to Master Landlord, provided that Master Landlord
shall not (1) be liable for any previous act or omission of Subsublandlord under
this Subsublease; (2) be subject to any 


                                       12

<PAGE>   16

defense or offset previously accrued in favor of Subsubtenant against
Subsublandlord; or (3) be bound by any previous payment by Subsubtenant of more
than one month's rent.


       14.    Miscellaneous.

              (a) The obligations of Subsublandlord hereunder accruing at any
time shall be binding only upon the owner, at that time, of the leasehold estate
under the Master Lease, and each purchaser or transferee of such leasehold
estate shall be deemed to have assumed the obligations of Subsublandlord
hereunder accruing during the period of its ownership. Subsublandlord's
liability under this Subsublease and any other liability of Subsublandlord
relating or with respect to the Premises shall be limited to Subsublandlord's
leasehold estate under the Master Lease and any judgment entered against
Subsublandlord on or with respect to such liability may be enforced only against
such leasehold estate, any other recourse being expressly waived by
Subsubtenant.

              (b) Subsublandlord shall have no liability to Subsubtenant on
account of any failure or refusal by Master Landlord to grant any approval or
consent. Moreover, Subsublandlord shall have no liability to Subsubtenant on
account of any failure or refusal by Subsublandlord to grant any approval or
consent. In any instance in which Subsublandlord is required by any provision of
this Subsublease (including any of the Incorporated Provisions as incorporated
herein) or applicable law to not unreasonably withhold consent or approval,
Subsubtenant's sole remedy shall be an action for specific performance or
injunction requiring Subsublandlord to grant such consent or approval, all other
remedies which would otherwise be available being hereby waived by Subsubtenant.

              (c) Subsubtenant represents and warrants to Subsublandlord that
Subsubtenant has dealt with no broker, agent or finder in connection with this
Subsublease other than C.B. Commercial, and Subsublandlord represents and
warrants to Subsubtenant that Subsublandlord has dealt with no broker, agent or
finder in connection with this Subsublease other than John Gillespie (all two
(2) together, the "Recognized Brokers") and Subsubtenant and Subsublandlord each
hereby agree to indemnify the other against any claim for commission or other
compensation in connection with this Subsublease made against the other party by
any broker, agent or finder other than the Recognized Brokers, including
attorneys fees incurred by such other party in the defense of any such claim.

CB Commercial as representative of Subsubtenant shall be paid a commission by
Subsublandlord equal to 3% of the Fixed Rent as defined in Paragraph 4.1 of the
Subsublease for the entire term based on the Premises subsubleased by
Subsubtenant. In addition, John Gillespie, as representative of Subsublandlord,
shall be paid a commission of 1.5% of the Fixed Rent as defined in Paragraph 4.1
of the Subsublease for the entire term based on the Premises subsubleased by the
Subsubtenant. The commission shall be due one-half at execution of the
subsublease 


                                       13

<PAGE>   17

and one-half prorated upon occupancy of Suite 200 and Suite 300 outlined in
Paragraph 2. Commission agreements between; Subsublandlord and C.B. Commercial
dated January 25, 1996, and Subsublandlord and John Gillespie dated January 25,
1996, have been executed by Subsublandlord. Should Subsublandlord not pay the
commission within 15 days of the commission due date, Subsubtenant, has the
right to pay C.B. Commercial and John Gillespie directly and offset such payment
against the amount of Rent payable under the Subsublease.

              (d) Except as provided in Section 4, this Subsublease contains the
entire agreement between the parties and all prior negotiations and agreements
are merged in this Subsublease. Any agreement hereafter made shall be
ineffective to change, modify or discharge this Subsublease in whole or in part
unless such agreement is in writing and signed by the parties hereto. No
provision of this Subsublease shall be deemed to have been waived by
Subsublandlord or Subsubtenant unless such waiver be in writing and signed by
Subsublandlord or Subsubtenant, as the case may be. The covenants and agreement
contained in this Sublease shall bind and inure to the benefit of Subsublandlord
and Subsubtenant and their respective permitted successors and assigns.

              (e) In the event that any provision of this Subsublease shall be
held to be invalid or unenforceable in any respect, the validity, legality or
enforceability of the remaining provisions of this Subsublease shall be
unaffected thereby.

              (f) Capitalized terms used herein shall have the same meanings as
are ascribed to them in the Master Lease, unless otherwise expressly defined
herein.

              (g) The submission of this document by Subsublandlord to
Subsubtenant shall not constitute an offer by Subsublandlord and Subsublandlord
shall not be bound in any way unless and until this Subsublease is executed and
delivered by both parties.



       15.    Participation Agreement; Agreement Regarding Engineering and 
Construction Services.

              Subsublandlord and Subsubtenant acknowledge that Sublandlord has
entered into the following two agreements with Master Landlord; (1)
Participation Agreement dated as of June 27, 1989, pertaining to the transfer,
assignment and conveyance to Subsublandlord of an appreciated value interest (as
defined therein) in the Building, and (2) Agreement dated as of June 27, 1989,
wherein Sublandlord is granted the right to negotiate for and/or perform certain
engineering and construction related services in connection with the Building
(collectively, the "Unrelated Agreements"). Subsubtenant and Subsublandlord
acknowledge and agree that neither shall have any right or interest in any
respect whatsoever in the Unrelated Agreements arising from this entry into this
Subsublease or otherwise.


                                       14

<PAGE>   18

       16.    Binding Effect.

              This Subsublease shall be binding on the parties hereto only upon
full execution and delivery of this Subsublease by both Subsublandlord and
Subsubtenant's and acknowledgment by Master Landlord. Syndicated Office Systems,
Inc. and Tenet Healthcare Corporation shall be jointly and severally liable for
Subsubtenant's obligations under this Subsublease.


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

                        SUBSUBLANDLORD

                        AMERIQUEST TECHNOLOGIES, INC.

                        By:
                           ---------------------------------

                        Its:
                            --------------------------------



                        SUBSUBTENANT:

                        SYNDICATED OFFICES SYSTEMS, INC

                        By:
                           ---------------------------------

                        Its:
                            --------------------------------



                        TENET HEALTHCARE CORPORATION

                        By:
                           ---------------------------------

                        Its:
                            --------------------------------



                                       15