Boy, I hate to be the ney-sayer, but this normally will not happen.
the only true explaination to variations in zoanthid color morphs is location, water conditions and sexual cross fertilization.
Placing corals next to one another will not create a color morph.
That's like placing my beat up Saturn next to a Shelby hoping to get some of it attributes...
Anyway, I don't mean to say that the idea has no meritt, but it just doesn't happen that way. Corals have built in defense mechanisms (palytoxins in zoanthids) that prevent other corals (zoanthids) from just connecting to them and changing the colors/species. As with other corals, when they encounter each other, the more agressive coral will out compete for space by growing over the other.
In the wild, if you encounter a mixed colony, be sure that it is at war. If they're both aggressive, then the war can last a long time. Plus there is also the potential to have enormous growing areas.
Yet, there is also the very common occurance of corals changing colors when they arrive in our individual tank; even tank to tank.
Browns turn red/purple/green/yellow/blue... And vise versa.
Then there is chemically enhanced corals (painted fish :lol: ) by using certain chemicals that claim to bring out brighter color from corals. That is a whole other topic most people aren't ready to tackle.
Otherwise, when I see two completely different zoanthid colonies form one animal, then I'll believe it. Hasn't happened yet...
Bill