The mushies will probably kill the colt so close, or the colt will possilbly kill them when it "lies down" at night. Definately move them apart, then they will be fine together.
This applies to all corals pretty much, also remember to give them space to grow, and that they can kill each other by releasing toxins even if they aren't touching each other.
Your aquarium is pretty much a giant battlefield between corals as they fight for space and their spot in the sun. Do your best to keep the peace. Use lots of GAC.