I have one last bridge to cross.

This one is proving to be giving the biggest headache.

Can you tell me how I can hook into the following part of groups-templatetags so I can conditionally change the status of a group.

function bp_group_status() {
259	        echo bp_get_group_status();
260	}
261	        function bp_get_group_status( $group = false ) {
262	                global $groups_template;
263
264	                if ( !$group )
265	                        $group =& $groups_template->group;
266
267	                return apply_filters( 'bp_get_group_status', $group->status );
268	        }
269

I have tried to do the following

function ct_group_is_member( $group = false ) {
        global $bp, $groups_template;

        // Site admins always have access
        if ( is_site_admin() )
                return;

    $current_user = $bp->loggedin_user->id;
    $current_institution = get_usermeta($current_user,"institution");

        // Load group if none passed
        if ( !$group )
                $group =& $groups_template->group;

        // Check membership
        if ( $current_institution<>groups_get_groupmeta($group->id,"institution" )) {
                $group->status = 'hidden';
        } else {
                return;
    }
        // Return
//        return apply_filters( 'ct_group_is_member', $is_institution );
}
add_filter ( 'bp_get_group_status', 'ct_group_is_member', 5, 2 );

Thanks HEAPS in advance
V