Mass. Gen. Laws ch. 223 § 39A
In an action against insurance companies severally liable upon a policy of insurance issued under section one hundred and two A, one hundred and eleven A or one hundred and seventeen A of chapter one hundred and seventy-five, or jointly and severally liable upon a policy of insurance issued under said section one hundred and eleven A, or in a suit against insurance companies brought by a judgment creditor under section one hundred and thirteen of said chapter one hundred and seventy-five and clause ten of section three of chapter two hundred and fourteen under a policy of liability insurance issued under said section one hundred and eleven A, service upon any one of said companies shall be a valid and sufficient service upon all of such companies as are named in the process. Such service, if on a domestic company, shall be made in the manner provided in this chapter and, if on a foreign company, in the manner provided in section thirty-nine of this chapter, or in the third clause of section one hundred and fifty-one and section one hundred and fifty-four of said chapter one hundred and seventy-five.
Mass. Gen. Laws ch. 223, § 39A