Mix strawberries and 1 1/2 cups sugar. Let stand 1 hour.
Heat oven to 425º. Mix baking mix, milk, cherries, 6 tablespoons sugar and the margarine until soft dough forms. Turn dough on surface lightly dusted with baking mix; gently roll in baking mix to coat. Shape dough into ball; knead 8 to 10 times.
Roll dough 1/2 inch thick. Cut with floured 3-inch star-shaped or round cutter. Place about 1 inch apart on ungreased cookie sheet. Bake 10 to 12 minutes or until golden brown.
Stir blueberries into strawberries. Beat whipping cream and 2 tablespoons sugar in chilled medium bowl with electric mixer on high speed until stiff. Split shortcakes in half while hot. Fill and top with berries and whipped cream.