Zend_Auth is a singleton, so you can't. What I do is to use Zend_Acl ensure that only users with a role of "admin" can get at the administration stuff.
To create a second Auth object, in principle, you could derive Zend_Auth to App_Auth and use a different session namespace. I've never tried this, but my starting code would look like this:
class App_Auth
{
/**
* Returns the persistent storage handler
*
* Session storage is used by default unless a different storage adapter has been set.
*
* @return Zend_Auth_Storage_Interface
*/
public function getStorage()
{
if (null === $this->_storage) {
/**
* @see Zend_Auth_Storage_Session
*/
require_once 'Zend/Auth/Storage/Session.php';
$this->setStorage(new Zend_Auth_Storage_Session('App_Auth'));
}
return $this->_storage;
}
}
It's possible that you have to override more.