title: In Keystone js v6, can `withAuth` have multiple listKeys, so users can authenticate against different lists?
body: <p>Out of the box, Keystone's auth is straight forward and nice and I want to continue using it, however I would like to set up different schema for the users of my front end than the standard Users schema used for the Keystone admin UI.  I know I don't need to and could just use the one table however the schemas are so different I'd like to know if I can, for example, keep using the <code>authenticatedItem { ... on User {} }</code> with Keystone and, in my front end queries, use something like <code>authenticatedItem { ... on DifferentUser {} }</code>.</p>
  <p>Thanks</p>