Stir pineapple gelatin into a bowl with boiling water until dissolved. Drain pineapple, reserving 1/4 cup of juice. Pour juice into the gelatin mixture; add vodka, rum, and cold water. Stir well. Place 1 pineapple chunk in each cup. Pour the gelatin mixture on top. Refrigerate for 1 hour. Freeze for at least 30 minutes before serving.