(cf SCR Part 8, rule 2; DCR Part 7, rule 2; LCR Part 6, rule 2)
(1) Two or more persons may be joined as plaintiffs or defendants in any originating process if--(a) separate proceedings by or against each of them would give rise to a common question of law or fact, and(b) all rights of relief claimed in the originating process are in respect of, or arise out of, the same transaction or series of transactions,or if the court gives leave for them to be joined.
(2) Leave under subrule (1) may be granted before or after the originating process is filed.