MERCK-MEDCO MANAGED CARE, LLC, Plaintiff-Appellant, v. RITE AID CORPORATION; EAGLE MANAGED CARE CORPORATION, a Subsidiary of Rite Aid Corporation; GIANT FOOD, INC.; EPIC PHARMACY NETWORK, INCORPORATED; NEIGHBORCARE PHARMACIES, INCORPORATED, Defendants-Appellees, NATIONAL PRESCRIPTION ADMINISTRATORS, INCORPORATED, Movant., 201 F.3d 436