3. Procedure where defendant is suing plaintiff.

Where any of the defendants in an interpleader-suit is actually suing the plaintiff in respect the subject-matter of such suit, the Court in which the suit against the plaintiff is pending shall, on being informed by the Court in which the interpleader-suit has been instituted, stay the proceedings as against him; and his costs in the suit so stayed may be provided for in such suit; but if, and in so far as, they are not provided for in that suit, they may be added to his costs incurred in the interpleader-suit.