public static function isNationalTransaction($iban1, $iban2)
    {
        // remove whitespaces
        $iban1 = preg_replace('#\s+#','',$iban1);
        $iban2 = preg_replace('#\s+#','',$iban2);

        // check the country code
        if(stripos($iban1,substr($iban2,0,2)) === 0)
            return true;
        else
            return false;
    }