GRILL DIRECTIONS: Cut steak into 1-inch pieces. Place steak, mushrooms, bell pepper and zucchini in resealable food storage plastic bag. Pour dressing over steak and vegetables; add marjoram. Seal bag; turn several times to coat. Refrigerate at least 2 hours to marinate, turning occasionally.
Heat grill. Remove steak and vegetables from marinade; reserve marinade. Alternately thread steak and vegetables onto six 12 to 14-inch metal skewers. Brush with reserved marinade.
When ready to grill, place kabobs on gas grill over medium heat or on charcoal grill 4 to 6 inches from medium coals; cover grill. Cook 6 to 8 minutes or until steak is of desired doneness, turning 2 or 3 times and brushing occasionally with marinade. Discard any remaining marinade.