Mass. Gen. Laws ch. 240, § 8: Guardian ad litem

Section 8. If, after notice has been given or served as provided in the preceding section and the time limited in such notice for the appearance of the defendants has expired, the court finds that there are or may be defendants not actually served with process within the commonwealth who have not appeared in the action, it may of its own motion, or on the representation of any party, appoint a guardian ad litem or next friend of any such defendant, and if any such defendants have or may have conflicting interests, it may appoint different guardians ad litem or next friends to represent them.