What is the test for a plaintiff to bring an action on behalf of third parties?

Under that test, the federal courts recognize the right of litigants to bring actions on behalf of third parties, provided the litigant: (a) has suffered an injury in fact sufficient to inspire concrete interest in the outcome of the case; (b) has a close relation to those third parties; and (c) is free of some hindrance obstructing the third parties' ability to protect their own interests (Powers v. Ohio, 499 U.S. 400, 410411, 111 S.Ct. 1364, 113 L.Ed.2d 411 [1991] ).