A plaintiff or defendant need not be interested in obtaining or defending against all the relief demanded. Judgment may be given for one or more of the plaintiffs according to their respective rights to relief, and against one or more defendants according to their respective liabilities. Unwilling plaintiffs who could join under this rule may be joined by a plaintiff as defendants, and the defendant may make any persons who could be joined under this rule parties by alleging their interest therein with a prayer that their rights in the controversy be determined, along with any counterclaim or cross-claim against them, if any, as if they had been originally joined as parties.
Ind. R. Civ. P. 20