firm). "The governing rule in these circumstances is that the possessor of the claimed privilege or right may intervene to assert it." Id. (quoting Appeal of Hughes, 633 F.2d 282, 288 (3d Cir. 1980)). See also US Bank Nat. Ass'n v. PHL Variable Ins. Co., No. 12 CIV. 6811 CM JCF, 2012 WL 5395249, at *2 (S.D.N.Y.