R.I. Gen. Laws § 36-10-6: Agreements for federal contributions.

The retirement board shall have the authority to enter into agreements with the federal government or appropriate agencies thereof respecting grants, contributions, or reimbursements to be made by the federal government as an equitable share in the cost of providing the annuities, benefits, and retirement allowances for those members of the system whose compensation is paid, in whole or in part, by the federal government or for whose compensation the state receives reimbursement, in whole or in part, from the federal government.