Here is the ULTIMATE SOLUTION:
At the pulldown, have a choice to "Add Email 4" or "Add Email 5" just like said above.
Then, have a simple little checkbox that says "Do Not Show Email in Address Book" for any of the emails I have in my list (e.g., 1-5), so I don't have to see a certain email of someone's showing up when I am composing an email and then searching for an address.
BUT, I can still have ANY old email of a friend or colleague stored with him as a contact (and linked to all the past emails I received from him). So, say now he works at a new place of work or business or simply decides to change his email, I can still know know ALL the past emails from any old email that came from this contact AND still choose the latest email (or the emails without the checkbox filled "Do Not Show Email in Address Book") when composing an email.
Then, outlook can still use ALL the emails (e.g., 1-5) in the algorithms for the outlook social network connector analysis for this contact.
WIN - WIN!!