N.Y. C.P.L.R. 1501

§ 1501. Actions against persons jointly liable; service of summons;\njudgment. Where less than all of the named defendants in an action based\nupon a joint obligation, contract or liability are served with the\nsummons, the plaintiff may proceed against the defendants served, unless\nthe court otherwise directs, and if the judgment is for the plaintiff it\nmay be taken against all the defendants.\n