How to use group avatar as blog avatar?

Hello guys!!!

I'm trying to do a thing that is breaking my head...

I have a BuddyPress+WPMU install... When a user creates a blog, on the blogs directory appears the blog and the user avatar...

I use BP Groupblog plugin to use a WPMU avatar as group blog, so, I want blogs to use group avatar instead of user avatar, is there a way to do that?

Thanks