1. In a small bowl, whisk oil, vinegar, ketchup, garlic, Worcestershire sauce and seasonings. Pour 1/2 cup marinade into a large resealable plastic bag. Add beef; seal bag and turn to coat. Pour remaining marinade into another large resealable plastic bag. Add mushrooms, onions, tomatoes and peppers; seal bag and turn to coat. Refrigerate beef and vegetables 8 hours or overnight.
2. Drain beef, discarding marinade. Drain vegetables, reserving marinade for basting. On six metal or soaked wooden skewers, alternately thread beef and vegetables.
3. Grill, covered, over medium heat or broil 4 in. from heat 9-12 minutes on each side or until beef reaches desired doneness and vegetables are crisp-tender, turning occasionally. Baste with reserved marinade during the last 5 minutes. Yield: 6 servings.