In the event that a commission is appointed the court may direct that not more than two additional persons serve as alternate commissioners to hear the case and replace commissioners who, prior to the time when a decision is filed, are found by the court to be unable or disqualified to perform their duties. An alternate who does not replace a regular commissioner shall be discharged after the commission renders its final decision. Before appointing the members of the commission and alternates the court shall advise the parties of the identity and qualifications of each prospective commissioner and alternate and may permit the parties to examine each such designee. The parties shall not be permitted or required by the court to suggest nominees. Each party shall have the right to object for valid cause to the appointment of any person as a commissioner or alternate. If a commission is appointed it shall have the authority of a master provided in Rule
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(c) and proceedings before it shall be governed by the provisions of Rule
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(d). Its action and report shall be determined by a majority and its findings and report shall have the effect, and be dealt with by the court in accordance with the practice, prescribed in Rule
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(e), (f), and (g). Trial of all issues shall otherwise be by the court.