From William's-Sonoma book entitled "Cocktail Parties". Perfect for an outdoor luau, it turns out a pretty pale pink if you use light rum. The grapefruit juice ensures that it's not too sweet since I don't like really sweet drinks. Very refreshing! I have doubled this recipe and it works out well so I'm sure it could be made in a large batch. Also, I wouldn't consider compromising the recipe by using canned juices. I have a juicer and juice fresh pineapple which makes the drink really frothy and delicious!!