Place chopped mango in a blender jar, add half the mango juice and blend till smooth. Add more mango juice if required.
Similarly blend chopped pineapple and half the pineapple juice till smooth. Add more pineapple juice if required. Lastly blend chopped grapes and half the grape juice till smooth. Add more grape juice if required.
Fill each glass first with mango slush, follow with grape slush and lastly with pineapple slush. Serve immediately.