The bureau and appeal tribunal shall not be bound by common law or statutory rules of evidence or by technical rules of procedure, but any hearing or appeal before such tribunals must be conducted in such manner as to ascertain the substantial rights of the parties. The bureau shall adopt reasonable regulations governing the manner of filing appeals and the conduct of hearings and appeals, consistent with the provisions of the North Dakota unemployment compensation law. When the same or substantially similar evidence is relevant and material to the matters in issue in claims by more than one individual or in claims by a single individual with respect to two or more weeks of unemployment, the same time and place for considering each such claim may be fixed, hearings thereon jointly conducted, a single record of the proceedings made, and evidence adduced with respect to one proceeding considered as introduced in the others when, in the judgment of the appeal tribunal having jurisdiction of the proceeding, such consolidation would not be prejudicial to any party. No person may participate on behalf of the bureau in any case in which the person has a direct or indirect interest.