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!