Heat pineapple to boiling. Dissolve jello in hot pineapple; stirring constantly. Let cool. Add 2 cups buttermilk. Beat well. Add Cool Whip. (I beat with mixer.) Chill.
Bring pineapple to a boil. Add peach Jello and plain gelatin dissolved in ... the meantime add buttermilk to Cool Whip. Add Cool ... mold. Serve when firm.