MIX 1 lb. lean ground beef with 2 Tbsp. Bull's-Eye Barbecue Sauce; shape into 4 patties. Place on medium heat on barbecue. Grill 8 to 10 min. or until cooked through, turning once and brushing with additional 2 Tbsp. barbecue sauce.
PLACE 1 sliced red pepper, green pepper and onion on centre of large sheet heavy-duty aluminum foil. Top with 1/4 cup barbecue sauce. Bring up foil sides. Double fold top and ends to form packet. Grill along with burgers 10 to 12 min.
FILL split kaiser rolls with burgers; top with barbecued vegetables.