The third-party defendant shall assert defenses to the third-party plaintiff's claim as provided in rule 1.441 and counterclaims against the third-party plaintiff as provided in rule 1.241 and cross-claims against other third-party defendants as provided in rule 1.245.
The third-party defendant may assert against the plaintiff any defenses which the third-party plaintiff has to the plaintiff's claim. The third-party defendant may also assert any claim against the plaintiff arising out of the transaction or occurrence that is the subject matter of the plaintiff's claim against the third-party plaintiff, and the plaintiff shall assert defenses as provided in rule 1.441 and counterclaims under rule 1.241.
The plaintiff may assert any claim against the third-party defendant arising out of the transaction or occurrence that is the subject matter of the plaintiff's claim against the third-party plaintiff, and the third-party defendant thereupon shall assert defenses as provided in rule 1.441, counterclaims as provided in rule 1.241, and cross-claims as provided in rule 1.245. Any party may move to strike the third-party claim or for its severance or for separate trial. A third-party defendant may proceed under this rule against any person not a party to the action who is or may be liable for all or part of the claim made in the action against the third-party defendant.
Iowa. R. Civ. P. 1.246