Mass. Gen. Laws ch. 65B § 2
In any case in which this commonwealth and one or more other states each claims that it was the domicile of a decedent at the time of his death, and no judicial determination of domicile for death tax purposes has been made in any of such states, any executor, or the taxing official of any such state, may elect to invoke the provisions of this chapter. Such election shall be evidenced by the sending of a notice by registered mail, receipt requested, to the taxing officials of each such state and to each executor, ancillary administrator and interested person. Any executor may reject such election by sending a notice by registered mail, receipt requested, to the taxing officials involved and to all other executors within forty days after the receipt of such notice of election. If such election be rejected, no further proceedings shall be had under this chapter. If such election be not rejected, the dispute as to the death taxes shall be determined solely as hereinafter provided, and no other proceedings to determine or assess such death taxes shall thereafter be instituted in the courts of this commonwealth or otherwise.
Mass. Gen. Laws ch. 65B, § 2