Subject to rulings by the agency upon objections a deposition taken and filed as provided in this rule will not become a part of the record in the proceeding until received in evidence by the agency upon its own motion or the motion of any party. Except by agreement of the parties or ruling of the agency, a deposition will be received only in its entirety. A party does not make a party, or the privy of a party, or any hostile witness his witness by taking his deposition. Any party may rebut any relevant evidence contained in a deposition whether introduced by him or any other party.