2 1/2 cups cups drained sliced jarred mangoes in juice (about 1 ¼ 26-ounce jars), ¼ cup juice reserved
1 1/4 cups gold tequila
1 cup frozen limeade concentrate
7 cups ice cubes
10 slices lime slices
Place sugar on plate and ¼ cup mango juice on another plate. Dip each of 10 margarita glasses into juice, then sugar.
Puree half each of mangoes, tequila, Grand Marnier and limeade in blender until smooth. Add 3 ¾ cups ice cubes; blend. Pour mixture into pitcher. Repeat with remaining ingredients. Pour margaritas into glasses. Garnish with lime slices.