For each flavor, dissolve one box of gelatin in 1 cup of boiling water.
Pour into a container and chill 3 hours or until firm.
After chilling the four flavors, cut them into small cubes.
In a separate bowl, sprinkle 2 envelopes unflavored gelatin into 1/2 cup cold water.
Let stand 1 minute.
Stir in 1 1/2 cups boiling water.
Add the can of condensed milk.
Mix well and cool.
Pour cooled milk mixture over gelatin cubes and chill a minimum of 3 hours or until firm.
Cut into blocks or shapes and serve!