MEMORANDUM AND ORDER Plaintiff Liberty Mutual Insurance Company brings the instant action against Defendant Sterling Insurance Company for a declaratory judgment: (1) requiring Defendant to provide primary insurance coverage for a third party in an underlying state court case (the “Underlying Action”); and (2) ordering a money judgment against Defendant for Plaintiff’s litigation costs in the Underlying Action. Defendant moves to dismiss pursuant to Federal Rule of Civil Procedure 12(b)(7) for failure to join a required party, or alternatively for an order requiring that Plaintiff join several third parties. BACKGROUND1 At a live music concert on July 29, 2018, Elliot Braha got into an altercation with Ryan Morales (“Ryan”), a non-verbal autistic man.2 (Compl. 9, ECF No. 1; Brian Hayes Aff. Supp. Def.’s Mot. Join Req’d Parties Alt. Dismiss Compl. (“Hayes Aff.”) 9, Ex. F at 3, ECF No. 14 1.) On August 23, 2018, Leonardo Morales (“Morales”), as legal guardian of Ryan, commenced an action (the “Underlying Action”) in the Supreme Court of the State of New York, Kings County. (Compl. 7; see Hayes Aff., Ex C.) The original complaint in the Underlying Action lodged claims against Live Nation Inc. and Braha. (Hayes Aff., Ex. C.) On December 17, 2018, Morales filed an amended complaint in the Underlying Action, adding Live Nation Worldwide Inc. as a defendant. (Brian Casey Aff. Reply Opp. Mot. Join Req’d Parties Alt. Dismiss. Compl. (“Casey Aff.”), Ex. A, ECF No. 17.) On December 19, 2018, Morales signed a stipulation of discontinuance with prejudice as to Live Nation, Inc., leaving Braha and Live Nation Worldwide Inc. as the remaining defendants. (Shafirstein Decl. 3, Ex. A, ECF No. 16.) Plaintiff and Defendant are each insurers of Braha, with Defendant serving as Braha’s primary insurer and Plaintiff serving as Braha’s excess insurer. (Compl.