In smaller environments, stick to pairs. I wouldn't really recommend harems of them, unless the tank is large. Same goes for the sankeyi, indigo, neon, springeri, flavivertex, etc.
A lot of the more aggressive pseudos, sometimes will kill their mates, when kept in pairs. And most of the large ones, need a big tank for a pair, and usually it should be a species tank.
Check out this cool vid: http://vimeo.com/6161531
P.fridmani lives in harems in the wild.
You will always see them in groups.
Its also easy to seperate the males by its longer find and females are more rounded.
In tanks they will also do good as small groups, but they need space for that.
Are you getting wild or captive bred?
i hope to get captive bread. Have you bred these guys?