N.Y. General Associations Law § 13

§ 13. Action or proceeding against unincorporated association. An\naction or special proceeding may be maintained, against the president or\ntreasurer of such an association, to recover any property, or upon any\ncause of action, for or upon which the plaintiff may maintain such an\naction or special proceeding, against all the associates, by reason of\ntheir interest or ownership, or claim of ownership therein, either\njointly or in common, or their liability therefor, either jointly or\nseverally. Any partnership, or other company of persons, which has a\npresident or treasurer, is deemed an association within the meaning of\nthis section.\n The service of summons, subpoena or other legal process of any court\nupon the president, vice president, treasurer, assistant treasurer,\nsecretary, assistant secretary, or business agent, in his capacity as\nsuch, shall constitute service upon a labor organization. Such service\nshall be made on such individuals in the manner provided by law for the\nservice of a summons on a natural person.\n