Mont. Code Ann. § 25-4-404
25-4-404 Cross-claim to be asserted in answer
25-4-404 . Cross-claim to be asserted in answer. When the judgment may determine the ultimate rights of two or more defendants as between themselves, a defendant who requires a determination shall demand it in the answer. The controversy between the defendants may not delay a judgment to which the plaintiff is entitled unless the court otherwise directs.