adding columns based on lists
 

I have a data cleaning function that I perform regularly and would like to
automate. The tables that I work with have a "Phone Number" field. I want
to automatically add 2 new fields called "Prefix" and "Suffix" in the first
empty columns, and based on the echange of the phone number, populate the 2
new fields. For records with exchanges in my list of 6 exchanges, I want one
set of values to be returned, and for all other records, I want a different
set of values to be returned. Can somebody please help me figure out how to
do this?

Thanks,
Craig