§6310. Joinder of others as defendants; notice
In any action brought for the redemption of mortgaged premises, when it is necessary to the attainment of justice that any other person besides the defendant, claiming an interest in the premises, should be made a party with the original defendant, the court on motion may order him to be served with an attested copy of the complaint amended in such manner as it directs, and on his appearance, the cause shall proceed as though he had been originally joined.