(a) The comptroller shall adopt rules specifying the circumstances under which it is advantageous for the state to allow a state agency to purchase goods or services under a contract made by another state agency other than the comptroller, including as provided under Subchapter I.
(b) If comptroller rules allow other agencies to make purchases under a contract entered into by an agency using delegated purchasing authority, the agency purchasing under delegated authority may offer the goods or services available under the contract to other agencies only if the agency first:
(1) establishes that the goods or services being offered under its contract are not available under a contract administered by the comptroller; and
(2) informs the comptroller of the terms of the contract and the capabilities of the vendor.