BuddyPress.org

You can filter the blogs using “bp_blogs_get_blogs” located in bp-blogs.php.
You’d then have to write your own blog fetch routine (yeah I know a pain!).

If you’re not happy with this, post an enhancement ticket on BP Trac:
https://trac.buddypress.org/newticket

Login with the same credentials you use here on bp.org.