211-2 Wyo. Code R. § 2-13
(a) Any party may move for the joinder of persons to a case when necessary to accord complete relief to the parties. A motion for joinder shall be filed with the Board within the time limits of these rules, and served by certified mail on the proposed parties. The motion shall set forth the names and addresses of the proposed parties, state why the proposed parties are necessary for just adjudication, and notify the proposed parties as well as all other parties that a response to the motion must shall be filed with the Board within fifteen (15) days of service of the motion.
(b) Upon motion, the Board may order joinder if complete relief to the parties cannot otherwise be provided. The order shall be served by certified mail on the joined party. The Board in its discretion may proceed with a hearing without requiring joinder if its jurisdiction over the proposed parties can be acquired only by their consent or voluntary appearance; however, any order rendered therein does not affect the rights or liabilities of absent persons.
211-2 Wyo. Code R. § 2-13