(a) Except as otherwise provided in subsections (c) and (d), upon motion of a party to an agreement to arbitrate or to an arbitration proceeding, the court may order consolidation of separate arbitration proceedings as to all or some of the claims if:
(1) there are separate agreements to arbitrate or separate arbitration proceedings between the same persons or one of them is a party to a separate agreement to arbitrate or a separate arbitration proceeding with a third person;
(2) the claims subject to the agreements to arbitrate arise in substantial part from the same transaction or series of related transactions;
(3) the existence of a common issue of law or fact creates the possibility of conflicting decisions in the separate arbitration proceedings; and
(4) prejudice resulting from a failure to consolidate is not outweighed by the risk of undue delay or prejudice to the rights of or hardship to parties opposing consolidation.
(b) The court may order consolidation of separate arbitration proceedings as to certain claims and allow other claims to be resolved in separate arbitration proceedings.
(c) The court may not order consolidation of the claims of a party to an agreement to arbitrate which prohibits consolidation.
(d) An arbitrator shall decide whether to consolidate one or more grievances arising under a collective bargaining agreement.