My company just purchased an email list that has numberous duplicate emails.
It looks something like this:

First Name Last Name Email
Thomas Gordon
William Hughes
Robert Doby
Carter Burdette
Claudia Coscia
Christine Holland
Joel Hayhurst
Krista Bates
William Hayward
D Wade Cloud
John Sonderegger

We would like to remove all duplicate emails except for the first occuring
one so that it would look like this:

First Name Last Name Email
Thomas Gordon
William Hughes
Robert Doby
Carter Burdette
Claudia Coscia
Christine Holland
Joel Hayhurst
Krista Bates
William Hayward
D Wade Cloud
John Sonderegger


Is there some way to set up a filter to do this automatically? Thanks for
your help in advance!!