In a medium bowl, combine grapefruit juice, salt,pepper, and sugar.
Take 1/2 of the grapefruit and squeeze the juice into the bowl and mix it thoroughly with the grapefruit pulp and set the sauce aside.
In a large salad bowl, combine the cabbages, add the sauce, and massage the sauce into the cabbage for about 2-5 minutes. Add the remaining grapefruit on top and divide up the portions.
From the Dinner Co-op