protected function _getUserPriceSufix()
    {
        $sPriceSuffix = '';
        $oUser = $this->getArticleUser();

        if ($oUser) {
            if ($oUser->inGroup('oxidpricea')) {
                $sPriceSuffix = 'a';
            } elseif ($oUser->inGroup('oxidpriceb')) {
                $sPriceSuffix = 'b';
            } elseif ($oUser->inGroup('oxidpricec')) {
                $sPriceSuffix = 'c';
            }
        }

        return $sPriceSuffix;
    }