Layered Gelatin Salad

1 small pkg cherry gelatin
1 small pkg lemon gelatin
1 small pkg orange gelatin
1 small pkg lime gelatin
4 C boiling water, divided
2 1/2 C cold water, divided
2 envelopes unflavored gelatin
2 C milk
1 C sugar
2 C sour cream
2 tsp vanilla

Dissolve cherry gelatin in 1 cup boiling water. Add 1/2 cup cold water and stir till gelatin is dissolved. Pour into a 13 x 9 x 2-inch pan sprayed with cooking oil. Refrigerate until set, not firm. In a small saucepan sprinkle unflavored gelatin into 1/2 cup of water, allow to sit for one minute. Stir in milk and sugar and cook over medium heat, stirring constantly until gelatin and sugar are dissolved. Remove from heat, whisk in sour cream and vanilla until mixture is smooth and creamy. Spoon 1 2/3 cup of this creamy gelatin over layer of the cherry gelatin that has set. Chill until set but not firm. Prepare the remaining gelatin flavors as you did the cherry gelatin, alternating the layers of gelatin with the creamy gelatin mixture, allowing each one to set before adding the next layer. Refrigerate for seven to eight hours. Cut into small squares to serve.