Section 735 ILCS 5/2-405 - Joinder of defendants(a) Any person may be made a defendant who, either jointly, severally or in the alternative, is alleged to have or claim an interest in the controversy, or in any part thereof, or in the transaction or series of transactions out of which the controversy arose, or whom it is necessary to make a party for the complete determination or settlement of any question involved therein, or against whom a liability is asserted either jointly, severally or in the alternative arising out of the same transaction or series of transactions, regardless of the number of causes of action joined.(b) It is not necessary that each defendant be interested as to all the relief prayed for, or as to every cause of action included in any proceeding against him or her; but the court may make any order that may be just to prevent any defendant from being embarrassed or put to expense by being required to attend any proceedings in which such defendant may have no interest.(c) If the plaintiff is in doubt as to the person from whom he or she is entitled to redress, he or she may join two or more defendants, and state his or her claim against them in the alternative in the same count or plead separate counts in the alternative against different defendants, to the intent that the question which, if any, of the defendants is liable, and to what extent, may be determined as between the parties.