advanced excel formula help

Hi all,

First of all thanks for taking the time to help me with my excel problem. I'm attempting to solve a problem that has caused a huge time suck for me in importing information from excel sheets to my salesforce.com database. In the database, every contact has a unique ID which is a large alphanumerical code. However, the information I have in excel doesn't have these codes and just has the First and Last names of each contact.In order to know if any names in my list are already in the database, or to update their information if they are already in the database, I need to have their unique codes.

I'm hoping that I can make a master list in excel of all my contacts in the database with their unique code next to them (this part is easy). Then use it to add the unique code to other lists of names i have in excel (basically to check if they are already assigned a unique code, and if so, to have that code appear in the column before or after their name). This may sound complicated, but here is how it would look:

Column A and B would be the master list. A would be contacts name, B would be the unique code. Then column E would be a list of names I need to import. I'm looking for a formula that will look through column E for any matches to Column A and then automatically paste the corresponding ID from Column B in Column D when it finds a match (Column D would then have all the codes for the names in column E).

Is this possible? Does it even make sense lol?