In a bowl, dissolve gelatin mixes in boiling water; stir well. Add raspberries and cranberry sauce; mix well. Stir in pineapple. Let cool briefly. Add soda; pour into a 9-by-9-inch serving dish and refrigerate until set. Spread topping over gelatin; cut into squares.
For the topping, whisk together pudding mix and milk for 2 minutes; fold in topping.