You could, but you would have to move this code:
case "Super Administrator":
$comparisons[0] = array(TRUE, "".((isset($_SESSION['SuperAdminLogin']))?$_SESSION['SuperAdminLogin']:"") ."", 1, "".((isset($GLOBALS['WAGLOBAL_Admin_Password']))?$GLOBALS['WAGLOBAL_Admin_Password']:"admin") ."");
break;
to the HelperGroupRulesPHP.php file from the powercms to the user registration version. The rest of the files should be identical.