HEAT grill to medium heat.
MICROWAVE vegetables and water in microwaveable bowl covered with waxed paper on HIGH 5 to 7 min. or until potatoes are crisp-tender; drain well. Mix 1/3 cup cheese and dressing. Add to vegetables; mix lightly.
SPOON onto center of large sheet of heavy-duty foil sprayed with cooking spray; fold top and ends to make packet, leaving room for heat circulation inside. Place on upper shelf of grill.
GRILL 15 to 20 min. or until vegetables are tender. Cut slits in foil to release steam. Open packet carefully. Sprinkle potato mixture with parsley and remaining cheese.