protected function grouped_parent_exists($path) {
        // Search the tree structure to find out if one of the paths
        // above the $path is a grouped path.
        $patharray = explode('/', $this->get_parent_path($path));
        $groupedpath = '';
        $currentpos = &$this->groupedparentprefixtree;
        foreach ($patharray as $item) {
            // When the item isn't set in the array we know
            // there is no parent grouped path.
            if (!isset($currentpos[$item])) {
                return false;
            }

            // When we aren't at the start of the path, continue to build
            // a string representation of the path that is traversed.  We will
            // return the grouped path to the caller if we find one.
            if ($item != '') {
                $groupedpath .= '/'.$item;
            }

            if ($currentpos[$item] == array()) {
                return $groupedpath;
            }
            $currentpos = &$currentpos[$item];
        }
        return false;
    }