What to do for two contacts with same email with duplication check?

What to do for two contacts with same email with duplication check?

I need to check for duplicates on entering new contacts.  My problem is, when I enter the new contact, "do not allow duplicates" on the email address shows me the the email address is already being used. So I do a global search and go to the contact. 

If the result is a true duplicate, no problem, I don't add it.

But I have cases where two contacts in the same company use the same email address.  In this case, I want to allow a contact with a duplicate email address to be added.

What's the best way to handle this? What I need is, "do not allow duplicates unless I say so". Can anyone think of a way around this?  Should I put the contact in without an email address in this case? Or is there a creative way to use a second field to let me get the contact in with the same email address as another?

Thanks!  It's becoming a show stopper.