HEAT grill to medium heat. Pour 1/4 cup dressing over chicken in shallow dish; turn over to coat both sides of each breast. Refrigerate 10 min.
MEANWHILE, mix barbecue sauce, marmalade and remaining dressing.
REMOVE chicken from dressing; discard dressing. Grill chicken on covered grill 12 to 15 min. or until done (165°F), turning occasionally and brushing with barbecue sauce mixture the last few minutes.