A better variation. Same problem, but there are 6 balls, 3 colors (red, white and blue), and each pair of a color has one heavy and one light ball, ie there is a set of 3 heavy balls which are red, white, and blue, and a set of 3 light balls which are red, white, and blue. All heavy balls are the same weight, all light balls are the same weight.

What method results in the fewest uses of the balance to separate them properly?