POUR marinade over all remaining ingredients in resealable plastic bag. Seal bag; turn to evenly coat ingredients with marinade. Refrigerate 30 min. to marinate. Remove ingredients from marinade; discard bag and marinade.
PREHEAT grill to medium-high heat. Place 1 fish fillet in center of each of four 18x12-inch sheets of heavy-duty foil; top with one-fourth of the vegetable mixture. Bring up foil sides. Double fold top and ends to seal each packet, leaving room for heat circulation inside.
GRILL 10 min. or until fish flakes easily with fork. Cut slits in foil with sharp knife to release steam before opening each packet. Remove fish and vegetables from each packet to serving plate; drizzle evenly with the reserved liquid from bottom of packet.