The Board of Trustees of the Arkansas Public Employees' Retirement System shall have the authority to promulgate such rules as are necessary to provide for the participation of employers defined as public rehabilitative services corporations or other local units of government under the provisions of § 4-34-101 and such local units of government as are provided for under this Code. Provided, however, the board shall not admit or retain any employer whose participation in the Arkansas Public Employees' Retirement System would jeopardize the tax-qualified status of the plan under the Internal Revenue Code, 26 U.S.C. § 1 et seq., or that would subject the plan to additional federal requirements, or to any other consequence that the board would determine to be detrimental to the system.