Euphyllia species are one of the easiest and most interesting Corals to make mixed colonies of. Would only suggest mixing similar growth types meaning branching with branching and wall with wall to keep from overgrowing. I'm just now reintroducing them into my system and have started to collect E. parancora and E. paradivisa in mixed color morphs to make a large colony to go into my new tank upgrade.
Cheers, Todd