In a large container, dissolve sugar and gelatins in boiling water. Stir in the pineapple juice concentrate, lemon juice, drink mix and cold water. If desired, place in smaller containers. Cover and freeze, stirring several times.
Remove from freezer at least 1 hour before serving. Stir until mixture becomes slushy. Just before serving, place 9 cups slush mixture in a punch bowl; stir in 1 liter ginger ale. Repeat with remaining slush and ginger ale. Yield: about 6 quarts (about 25 servings).