This allows you to add lots of contacts at once, from across multiple address books.
Tap “Import” on the contacts page, then select “Contacts Checklist” to see a list of all the contacts on your device. Set a check mark against all the ones you want to add.
If a contact has more than one email address, they will each be shown.
No check mark will be available for addresses already in your group. (They are displayed here so that you can see that the contact already has an alternate address included.)