jQuery.fn.groupListElement = function() {

    var $list = $(this[0]);
    var args = arguments[0] || {};
    var groupClassName = args.groupClassName || 'li_group';
    var size = args.size || 2;

    if ( $list.length > 0 ) {

        var wrapper = '<li class="' + groupClassName + '"><ul></ul></li>';

        while ( $('> li[class!="' + groupClassName + '"]',$list).slice(0, size).length >= 1) {
            $('> li[class!="' + groupClassName + '"]',$list).slice(0, size)
                .wrapAll(wrapper);
        }

    }

    return $list;

};