While steak is grilling, place onions on a piece of heavy aluminum foil with a small amount of marinade and grill until slightly tender. Do not baste steak with marinade or add marinade to onions during the last 5 minutes of cooking time. Discard any remaining marinade. To serve, place steak on a platter and top with onions. Combine worcestershire sauce, salad dressing, barbecue sauce and minced garlic.
Place steaks in a shallow dish.
Pour mixture over top, making sure steaks are completely covered with sauce. Cover, then refrigerate for about 30 minutes. Grill over medium hot coals, turning one time and basting once on each side. Do not baste during last 5 minutes of grilling time. Discard remaining sauce.