They would contain that clause(below). Aha!
(d)Agreement. A service-disabled veteran-owned small business concern agrees that in the performance of the contract, in the case of a contract for -
(1) Services (except construction), at least 50 percent of the cost of personnel for contract performance will be spent for employees of the concern or employees of other service-disabled veteran-owned small business concerns;
These businesses would not be doing much of the work and would essentially be pressing a button to grant access from the large business concern. That contract FAR clause seems very similar to another CFR clause I believe might apply as well.
13 CFR 125.6
§ 125.6 What are the prime contractor's limitations on subcontracting?
(a)General. In order to be awarded a full or partial small business set-aside contract with a value greater than $150,000, an 8(a) contract, an SDVO SBC contract, a HUBZone contract, a WOSB or EDWOSB contract pursuant to part 127 of this chapter, a small business concern must agree that:
(1) In the case of a contract for services (except construction), it will not pay more than 50% of the amount paid by the government to it to firms that are not similarly situated. Any work that a similarly situated subcontractor further subcontracts will count towards the 50% subcontract amount that cannot be exceeded.
Thank you for the guidance.