Place raspberries in container of an electric blender; cover and process until smooth. Pour raspberry puree through a wire-mesh strainer into container, discarding pulp and seeds remaining in strainer. Add banana and 1 can juice concentrate; cover and process until smooth. Pour mixture into a large freezer-proof container. Stir in remaining concentrate and 2 cups water. Cover and freeze 4 hours or until slushy.
To serve, transfer juice mixture to a small punch bowl. Stir in mineral water, and serve immediately.