Massachusetts General Laws Part III. Courts, Judicial Officers and Proceedings in Civil Cases (Ch. 211-262) Ch. 217, § 7

If a judge or register desires to be appointed guardian of his minor child, who is an inhabitant of or resides in the same county, such appointment may be made, and all subsequent proceedings in regard thereto had, in the probate court of an adjoining county. A judge who is named as executor of or trustee under a will may be appointed as such except that, if such will is offered for probate in his county, such appointment shall be made, and all subsequent proceedings in regard thereto had, in the probate court of an adjoining county.