HEAT grill to medium heat.
POUR 1/4 cup dressing over chicken in shallow dish; turn to evenly 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 5 to 7 min. on each side or until done (165°F), brushing occasionally with sauce mixture for the last few minutes.