In a bowl, stir together the lime-flavored gelatin and 1 cup boiling water until gelatin dissolves. Stir in 1 cup cold water and the marshmallows. Chill until mixture is partially set (the consistency of unbeaten egg whites).
In a large bowl, stir together cream cheese and mayonnaise. Stir in pineapple and nuts. Fold in whipped cream. Fold in partially set lime-gelatin mixture. Transfer to a 3-quart rectangular baking dish. Cover and chill until almost firm.
Stir together raspberry-flavored gelatin and 1 cup boiling water until gelatin dissolves. Stir in 1 cup cold water. Pour over mixture in baking dish. Cover; chill until set. Makes 12 side-dish servings.