(1) Two or more persons may be joined (as applicants or respondents) in any proceeding:
(a) if separate proceedings by or against each of them would give rise to a common question of fact or of mixed fact and law; or
(b) if all rights to relief claimed in the originating application are in respect of, or arise out of, the same transaction or series of transactions; or
(c) by leave of the Court.
(2) Leave under paragraph (1)(c) may be granted before or after the originating application is filed.
(3) If 2 or more persons are joined under subrule (1), the Court may at any stage of the proceedings order that proceedings by or against any party or parties be conducted separately.