1. Partially cook onions: In 3-quart saucepan over high heat, heat onions and enough water to cover them to boiling. Reduce heat to low; cover and simmer 10 to 12 minutes until onions are almost tender. Drain.
2. Trim excess fat from pork butt; cut meat into 2-inch chunks. In large bowl, combine pork, onions, red peppers, and remaining ingredients except jelly. Cover and refrigerate at least 1 hour, stirring occasionally.
3. About 1 hour before serving, prepare outdoor grill for barbecuing.
4. On 6 long skewers, alternately thread pork chunks, onions, and red peppers, reserving marinade. Place skewers on grill over medium heat; cook 35 to 40 minutes until pork is tender, brushing meat and vegetables frequently with reserved marinade and turning skewers occasionally. Brush kabobs with apple jelly; cook 1 minute longer.