Combining two tables and separating duplicates

[susanohkwon]

Hello,

I have two different mailing lists, one from company A and one from
company B. To prevent company A & B from sending duplicate
invitations, I would like to combine the two lists in Access using e-
mail addresses as a unique identifier. How do I query to find and
separate the duplicates into a separate table. The desired end result
would be one final mailing list (the duplicates identified and Company
A's mailing information kept) and one list with all the duplicate
contacts?

Thanks in advance!