(a) A Petitioner or Respondent may name an Interested Party in a complaint or cross-complaint as a Party whose joinder in the Arbitration is demanded:

(b) At any time prior to a hearing on the merits, an Interested Party may be permitted to join in and be bound by the Arbitration proceedings if required by the terms of the Interested Party's contract or by the agreement of the Parties. Such joinder shall not be required if it unduly delays or complicates the expeditious conclusion of the Arbitration unless a failure to order joinder would be likely to produce inconsistent decisions from separate proceedings among the Parties.

(c) Where an Interested Party is made a Party to the Arbitration, the joinder shall be limited to the issues raised by the Respondent and Petitioner in the pleadings.