Milk Mixture: 1 can (14 oz) condensed milk
2 envelopes unflavored gelatin
1/4 c cold water
1 3/4 c hot water
Soften unflavored gelatin by sprinkling over cold water. Add hot water. Stir for 2 minutes. Add condensed milk. Stir. Set aside.
Gelatin Mixture: 4 boxes (3 oz each) jello, any flavor(s)/color(s)
5 c hot water, divided
4 envelopes unflavored gelatin
In a small bowl, stir together 1 box of jello and 1 envelope unflavored gelatin. Add 1/4 c hot water. Stir for 30 seconds to soften. Add 1 c hot water. Stir until gelatin dissolves. Pour into 9 x 13" pan and chill 20 minutes. While first layer is chilling, dissolve remaining boxes of jello/gelatin in separate bowls. Set aside.
After 20 minutes, carefully pour 1 cup of milk mixture over first jello layer in pan. Chill 20 minutes. Pour second jello layer over milk mixture. Chill 15 minutes. Pour 1 cup of milk mixture over jello layer. Chill 15 minutes. Pour third jello layer over milk mixture. Chill 15 minutes. Pour 1 cup of milk mixture over jello layer. Chill 15 minutes. Discard any extra milk mixture. Pour final jello layer over milk mixture. Chill 15 minutes before covering pan. When completely set, cut into bars or squares.