39. Joinder of Additional Parties
(1) The parties are free to agree on the procedure for joining an additional party to an arbitration, provided always that the party to be joined is party to the arbitration agreement or has consented to joinder.
(2) Absent such agreement, and before the confirmation or appointment of any arbitrator, the arbitral institution administering the arbitration or, where there is no such institution, the Court, may, upon the request of a party to the arbitral proceedings and if it considers that it is in the interests of justice to do so, allow one or more third parties to be joined to the arbitration, provided such person:
(a) is a party to the arbitration agreement; or
(b) has consented to joinder in writing,
unless the arbitral institution administering the arbitration or, where there is no such institution, the Court finds, after giving all parties, including the party or parties to be joined, the opportunity to be heard, that joinder should not be permitted because of prejudice to any of those parties.
(3) No additional party may be joined after the confirmation or appointment of any arbitrator, unless all parties, including the additional party, otherwise agree.