A friend brought this to our nephew's 1st birthday party, and was a big hit. It is very cool and refreshing.
Combine reserved pineapple juice with enough hot water to make 2 cups. Dissolve jello in this mixture.
Put jello mixture in blender with cream cheese and mix well. Pour into bowl and slowly add 7-Up. Chill until slightly thickened, then add pineapple and nuts. Chill until firm.