Once you log in as one persona, you can easily switch to another via the "switch persona" link. It will then bring up a list of all the personas under that email address. Assuming of course all your personas are under the same email address. If not then this won't work.

If they are, you can use any password for any of your personas to log in. I have Asenath, Catherine, Hui li and Helen. I can use Catherine's password to log in as Asenath and Hui's password to log in as Helen, etc... Assuming again, that all the personas are under the one email address.

:-D