Depends, according to Joyce Wilkerson's book, several False Percula's (Ocellaris) can be kept together in a single tank. However, only one spawning pair will form, the other two will remain juveniles. She supposedly has 4 Ocellaris in her own tank.
She then goes on to mention that True Perculas are not as mild mannered as Ocellaris in that they may attack tank mates. Doesn't go into detail as to how they may behave with each other. Looking at pages 65 thru 68 in Clownfishes.