(1) At any stage of a proceeding under rule 18.02 against one or more persons having the same interest, the Court may appoint one or more of:
(a) the defendants; or
(b) the persons as representing whom the defendants are sued, to represent some or all of those persons in the proceeding.
(2) Where the Court appoints a person who is not a defendant, it shall make an order under rule 9.06 adding the person as a defendant.