The problem with adding a group of cichlids to a community tank is when they start breeding, they will take over the tank. That is why it is best to only have 1 pr in a community tank, and have caves and stuff for them in one corner of the tank. That way they will take over the corner when breeding and the rest of the fish will be able to move around the rest of the tank and not get attacked. If you have a colony of cichlids, each female is going to need a foot of space and any fish going into that area will be attacked. If it's a single species tank, then it's not an issue.