Heat coals or gas grill for direct heat. Cut six 18x12-inch pieces of heavy-duty foil; spray each piece with cooking spray.
In large bowl, mix beef, cheese, Worcestershire sauce, chopped onions and 1 1/2 teaspoons of the peppered seasoned salt. Shape mixture into 6 patties, about 1 inch thick.
Place potatoes on center of each sprayed foil piece. Top with beef patty, carrots, tomatoes and sliced onions; sprinkle with remaining 1/2 teaspoon seasoned salt. Fold foil over patties and vegetables so edges meet. Seal edges, making tight 1/2-inch fold; fold again. Allow space on sides for circulation and expansion.
Cover and grill packets over medium heat 17 to 20 minutes, rotating packets 1/2 turn after about 8 minutes, until potatoes are tender. Place packets on plates. Cut large X across top of each packet; fold back foil.