Add 3/4 cup boiling water to 1 pkg. gelatin mix in medium bowl; stir 2 min. until completely dissolved. Add enough ice to 1/2 cup cold water to measure 1 cup. Add to dissolved gelatin; stir until slightly thickened. Remove any unmelted ice. Refrigerate 30 min. or until thickened but not set.
Beat with mixer on high speed 2 min. or until about doubled in volume. Spoon into 12 (8-oz.) jelly jars.
Repeat with each remaining gelatin flavor to make a total of 4 layers, refrigerating after each layer as directed.