N.Y. C.P.L.R. 601

§ 601. Joinder of claims. (a) The plaintiff in a complaint or the\ndefendant in an answer setting forth a counterclaim or cross-claim may\njoin as many claims as he may have against an adverse party. There may\nbe like joinder of claims when there are multiple parties.\n (b) Two or more plaintiffs may join no more than five claims in any\none action or proceeding against the same defendant arising out of\nseparate consumer credit transactions, provided that the plaintiffs are\nrepresented by the same attorney.\n