How to retrieve all email addresses in Facebook through API

Facebook users can add multiple email addresses. I know, with the extended "email" permission, you can retrieve the primary email address through the graph API. How do you retrieve the rest of the email addresses? This is important for my app so that I can find their exis开发者_StackOverflow社区ting account in my database rather than unnecessarily creating a new account.

The alternative email addresses are not available. They are not listed on the FQL table or the Graph API.