In a 2- or 3-quart saucepan slightly mash raspberries with potato masher. Stir in tea, cranberry-raspberry juice, lemonade, water, and allspice. Bring to boiling; reduce heat. Simmer, uncovered, for 10 minutes. Strain and discard fruit pulp and spices.
Ladle into heat-proof glass mugs or cups. Sweeten with sugar, if desired. Serve with lemon slices and additional raspberries, if desired. Makes 6 servings.