Mass. Gen. Laws ch. 240, § 24: Parties; subsequent purchasers as

Section 24. Whoever, during the pendency of proceedings for the division of flats, acquires by purchase, devise or descent, or by the enforcement of a mortgage or lien, an interest or title in or to any flats which are the subject matter of such proceedings, may by order of the court be made a party to such proceedings, and shall be chargeable with such share of the expenses as the court orders.