Puree raspberries and their liquid in electric blender container; set aside.
Dissolve gelatin in boiling water in small bowl; stir in pureed raspberries and lemon juice. Refrigerate until mixture mounds when dropped from spoon.
Reserve 6 peaches for garnish; chop remaining peaches. Fold chopped peaches into 1 cup prepared whipped topping.
Spread peach mixture into prepared crust; carefully top with gelatin mixture. Refrigerate until firm, about 3 hours. Top with remaining whipped topping and reserved peaches.