Use a citrus press or a juicer to juice the grapefruits, oranges, tangerines, and lime.
Juice the pomegranates (2/3 cup juice) into a separate container, and keep everything chilled.
When it is time to serve the drinks, fill each glass about ⅔ full with the citrus juice, and then top with the pomegranate. Due to it's density, the pomegranate will settle to the bottom, and the two juices will stay separated. Add a shot of silver tequila, and you have a real solstice treat!