My experience is that it generally doesn't work out well.
The best way to have multiple ATF is to get them all at the same time and to grow them out together. Different species tend to be fairly intolerant of each other, with the mesopredatory species being really nasty towards the keystone species. ATF also tend to be extremely intolerant toward anything new in the tank that looks even vaguely like another ATF.
Once they get a bit of size to them, even established groups are notorious for turning on each other. In the wild, ATF of all species school as juveniles, but become increasingly solitary as they grow. The only time they come together in the wild is for mating or in situations where there is a LOT of food around.
One thing that I noticed is that after I added a large arowana to the tank, who was always just calmly cruising around at the top, 'accidentally' dominating the ATF, most of my dominance issues stopped.
Still though, if MY money is on the line, I wouldn't mess around with mixed groups of ATF.
