I don't know what this is worth, but I'll share it anyway. I had a blue base mag for a little over a year. It was growing, eating, and doing fine. I purchased a red base mag, and placed it on the pedestal right next to the blue one. The blue one moved as if to get away from the red one. The blue one started to shrink, stopped eating, and started looking pretty bad. I separated the two so they weren't touching. The blue one spent the next couple of months trying to split. I finally helped it out with a razor blade. One half died, and I still have the other.
It's well documented that colonial anemones will do battle with other colonial anemones, even when we consider them the same species. I'm sure your experiment is possible, and it should be an incredible display when you're done. I'd just keep an eye out for stress when two are close together, and obviously not clone mates.