(1)Substitution of Parties. The Division may, on motion, at any time in the course of any proceeding, permit such substitution of parties as justice or convenience may require.(2)Intervention. Any party not initially joined in the action or proceeding shall be permitted to intervene. In the discretion of the Division, any person not a party may be permitted to intervene in any action or proceeding. A person or party desiring to intervene shall file a motion which shall state therein the grounds for intervention.