[r-a-y]

Try the BP Groupblog plugin instead:
https://wordpress.org/extend/plugins/bp-groupblog/

It’s been awhile since I’ve used BP Community Blog (back in the ol’ BP 1.0 days), but I believe it allows you to give a group access to an existing blog to post at. This wouldn’t be on the BP frontend. It’s more of a WP admin thing. Just glanced the code a bit, and I *think* the code should still hold up…