Mass. Gen. Laws ch. 175F, § 12: Trust instrument provisions

Section 12. The trust instrument may provide (a) that there shall be a minimum period during which any participant must participate in the fund; (b) that the fund may provide tail coverage to any participant which joins or withdraws from the fund; (c) that all participants shall execute a participation agreement; (d) that the trustee shall be free of all personal liability for his actions in good faith on behalf of the fund; and (e) that the trustee may be either an individual or an institution such as a bank, an insurance company or any other appropriate entity.