I think you have to be careful about adding more and more ways to qualify or specify a group in these environments. The more options and ways to categorize DF/PF/RF groups, the smaller the pool of groups to choose from becomes. Ultimately you could have dozens of groups in game waiting for players, but because of one option or another, no one is available to the other groups that are waiting and everyone continues to wait, and then the game appears barren of players because they never get a group.