The Federal Rules of Civil Procedure

(a) In General. A party asserting a claim, counterclaim, crossclaim, or third-party claim may join, as independent or alternative claims, as many claims as it has against an opposing party.

(b) Joinder of Contingent Claims. A party may join two claims even though one of them is contingent on the disposition of the other; but the court may grant relief only in accordance with the parties’ relative substantive rights. In particular, a plaintiff may state a claim for money and a claim to set aside a conveyance that is fraudulent as to that plaintiff, without first obtaining a judgment for the money.