Section 12. Upon acceptance of this chapter as herein provided, the appropriate public authorities of two or more governmental units may join together in negotiating and purchasing, as provided in section three, one or more policies of insurance providing the benefits set forth herein for the employees of all said governmental units. At their discretion said public authorities may establish a central administrative office and employ such personnel as may be necessary to carry out the provisions of this chapter. The requirements of clause (h) of subdivision (A) of section one hundred and ten and clause (e) of section one hundred and thirty-three of chapter one hundred and seventy-five that the policy be issued to the trustees of a fund shall not apply to the issuance of a policy insuring the employees of two or more governmental units pursuant to sections eleven and twelve of this chapter.

Two or more governmental units may also join together, by means of a trust or joint purchase agreement, when providing hospital, surgical, medical, dental and other health care coverage as authorized by this chapter. In lieu of or in addition to entering into the insurance policies, agreements or contracts described in this chapter, a trust or joint purchase group may enter into an administrative services or other contract with one or more insurance companies, nonprofit hospital, medical or dental service corporations organized under chapter one hundred and seventy-six A, chapter one hundred and seventy-six B or chapter one hundred and seventy-six E, or with one or more health care organizations, or with one or more third party administrators or other entities to organize, arrange or provide for the delivery or payment of health care coverage or services, as provided in section three A. In such case, the trust or joint purchase agreement shall make provisions for the allocation of the claims, administrative and other expenses of the trust or joint purchase group among the participating governmental units, and shall set forth a schedule pursuant to which the treasurer of each participating governmental unit shall forward to the treasurer of the trust or joint purchase group, from the governmental unit's claims trust fund, that governmental unit's allocation of the trust or joint purchase group's claims, administrative or other expenses. The requirements of section three A shall apply to any governmental unit which participates in any such trust or joint purchase agreement, except to the extent that those requirements would conflict with the provisions of this paragraph. Nothing in this section shall be construed to prevent two or more governmental units pursuant to a joint purchase or trust agreement from jointly negotiating and purchasing other coverage as authorized by this section.

The board of a trust or joint purchase group established by 2 or more governmental units may vote to implement changes to co-payments, deductibles, tiered provider network copayments and other cost-sharing plan design features which do not exceed those which an appropriate public authority may offer under section 22; provided, however, that each governmental unit that is a member of a trust or group shall comply with the requirements set forth in section 21 before any such changes may be applied to the health insurance coverage of such governmental unit's subscribers. If such changes to the dollar amounts for copayments, deductibles, tiered provider network copayments and other cost-sharing plan design features do not exceed those permitted under section 22, such changes shall be approved in accordance with the provisions of section 21.