Do what
>>4 said. But if you're not up to it (because that too could also lead to them just kicking you out of the group), simply deal with it. In middle school, I used to hate this girl but she was in our group of friends so I just hung out with her because she was there, not because I actually liked her. The thing is I vocalized that, but they never kicked me out because they liked me better than her, so unless you're sure they like you better than him, it might be best to just not say anything.
I don't know. Think about it for a while. How do you want to deal with this? What do you think will happen? Are you ready for the results of whatever you decide to do?