In your function, try using is_front_page() or is_home() instead of bp_is_front_page().
@r-a-y Tried those, no luck, again.
@jivany, thanks, but I’m not really following how to use the
locate_template( array( 'groups/index.php' ), false );
Pretty much ready to give up on it at this stage! Seems like it ought to be an easier thing than it is, but that’s usually the way of things…