This type of reply always gets ignored, but I'm not one to give up easily.
When it comes to a tank of mixed up cichlids we can manage to get New World fish to come to some sort of truce in an overstocked tank. They'll survive, though most of their natural behavior (territories, nesting, relationships of pairs/harems, spawning and breeding) are stripped away.
My opinion in these cases is to consider a tank of cichlids from lake Malawi. Not only are the fish so incredibly bold in color, but where new worlds will survive in a tank like this, these Malawi's thrive!
I guess I'm always more concerned about what's best for the fish, but afaic anyone who has only kept new worlds as single specimens in a mixed up tank has never really kept new worlds.
Please don't retaliate to this post guys, I know this is hardly the common opinion, but I thought I'd throw my honest opinion out there for good ol' Alabaster here.