title: Multiple Instances (2) of Zend_Auth
body: <p>I have a CMS built on the Zend Framework.  It uses <code>Zend_Auth</code> for "CMS User" authentication.  CMS users have roles and permissions that are enforced with <code>Zend_Acl</code>.  I am now trying to create "Site Users" for things like an online store.  For simplicity sake I would like to use a separate instance of <code>Zend_Auth</code> for site users.  <code>Zend_Auth</code> is written as a singleton, so I'm not sure how to accomplish this.</p>
  
  <p>Reasons I don't want to accomplish this by roles:</p>
  
  <ol>
  <li>Pollution of the CMS Users with Site Users (visitors)</li>
  <li>A Site User could accidentally get elevated permissions</li>
  <li>The users are more accurately defined as different types than different roles</li>
  <li>The two user types are stored in separate databases/tables</li>
  <li>One user of each type could be signed in simultaneously</li>
  <li>Different types of information are needed for the two user types</li>
  <li>Refactoring that would need to take place on existing code</li>
  </ol>