In a large bowl combine ground beef, 2 tablespoons soup mix, ¼ cup sour cream, 1 tablespoon Worcestershire sauce, and pepper; mix well (the mixture will be soft). Form the mixture into 4 burgers. Grill the burgers, turning once, until done (10 to 12 minutes); set aside. In a small bowl, combine the remaining soup mix, the remaining sour cream, and the remaining Worcestershire sauce; mix well. Place each grilled burger on a bun. Serve each burger with a dollop of dressing and garnish as desired.