It is possible if the tank is large enough. It depends on which trigger, how much room there is to hide and the personality of your individual fish. Personally, I'd go with a tougher clown like a tomato or cinnamon. :happyfish
IMO if the trigger is doclie, eg niger and small enough, however i have a small humma that will go after fish 3X his size, but i often think it is just a game of TAG...
ask you LFS to see if you can dring the clown back if it is an issue, but you could go for more live rock.. Let me know what you do??