Notwithstanding any other provision of law to the contrary, no rule promulgated by the department setting forth criteria for payment of fees by or integration of systems of an insurer and an entity administering claims involving injured employees shall apply to such parties, unless a contractual relationship between such parties to administer claims on behalf of one or more employers is established and the provisions of the rule are not contrary to specific terms in the contract.
§ 375.427, RSMo