735 ILCS 5/2-614: Joinder of causes of action and use of counterclaims.

(a) Any plaintiff or plaintiffs may join any causes of action, against any defendant or defendants; and the defendant may set up in his or her answer any and all cross claims whatever, whether in the nature of recoupment, setoff or otherwise, which shall be designated counterclaims.

(b) The court may, in its discretion, order separate trial of any causes of action, counterclaim or third-party claim if it cannot be conveniently disposed of with the other issues in the case. Legal and equitable issues may be tried together if no jury is employed.