Nah, I think when you start putting different types of coral close together you are asking for trouble.
Some things can touch each other fine, but I would play it safe whe you first introduce something to your tanks, and give them room.
I am totally supprised at what can be close and what cannot. Rigth now I have some green star polyps that are stinging some anthelia that spread to close, but I also have some montipora digitata that has zoanthids nestled right up next to it, they have grown that way and been like that for at least a year.
You can get away with crowding mushrooms, but I wouldn't try it with anything else.