Showing Group Activity on Sub site

Anybody know how to show activity from a group on a subsite of a BP/WPMU setup?

I'd like users to be able to create a blog and have a way of linking the site to a BuddyPress group on the main site. Ideally it would be really cool if the front end to a group could be embedded into the subsite. But for now just a widget that showed latest group activity would be good.

Any ideas?