Stir 1 cup of the boiling water into each flavor gelatin in separate bowls at least 2 min. until completely dissolved. Stir 1 cup of the cold water into each bowl. Pour into separate 9-inch square pans.
Refrigerate 4 hours or until firm. Cut gelatin in each pan into 1/2-inch cubes.
Layer alternating gelatin flavors and whipped topping in 8 dessert glasses.