You should see wild photos of BTAs. They are colonial animals and live in extremely close proximity to their neighbors. Generally it's a mass of clones, but you will see a few random variants in the bunch.
There are anemone dominated tanks with different species touching and everything is okay. Here's a recent thread with some proof.
http://reefcentral.com/forums/showthread.php?t=2508067
That being said I would err on the side of caution, I don't think this has been fully explored and replicated enough to say it's perfectly okay in every scenario.