STIR 3/4 cup of the boiling water into dry blue gelatin mix at least 2 min. until completely dissolved. Add 1/2 cup of the ice cubes; stir until ice is melted. Pour into pie crust; refrigerate 5 to 10 min. or until gelatin is set but not firm.
MEANWHILE, stir remaining 3/4 cup boiling water into dry red gelatin mix in separate bowl at least 2 min. until completely dissolved. Add remaining 1/2 cup ice cubes; stir until ice is melted. Cool 5 min. or until slightly thickened.
SPREAD whipped topping over blue gelatin layer; cover with red gelatin. Refrigerate 2 hours or until set. Store leftovers in refrigerator.