If it makes you feel any better at all, I don't have what it takes to handle a dog like that, either, and if I were in your position, I'd return him to the group. I'd feel sad and I'd feel guilty about it, but I'd do it, because somewhere is the perfect home for him. Also, somewhere is the perfect dog for you, and from what you've said here, he isn't it. Good luck with whatever you decide to do.