BuddyPress.org

Heh. That’s exactly what I did here, except by I did it by hand. Wish I’d known the plugin existed!

I used it for forums, of course, and you can too, if you do similar edits to:

forums/index.php

groups/single/forum.php

groups/single/forum/edit.php

groups/single/forum/topic.php

in your child theme, so it survives future upgrades.