Good morning/afternoon/evening everyone.  

I have recently encountered an issue and have been working with the premiere support for SFDC on the matter, however, it looks like there isn't going to be a non-programmatic solution.  So I thought I drop a line in here to see if anyone has encountered and crafted a solution/workaround for my issue.  I do give Kudos and always follow up on my threads.

Anyway, enough time wasting, here is my issue:

     The service cloud implementation I am working with requires that there be a few fields on the contact object of the EMAIL data type.  One of those fields is managerEmail__c.  All contacts in this implementation are actual employees of the organization, so they obviously have managers that also have their own contact record.  So, when a manager submits an email to case, the E2C process just looks for contact records with the email address that was sent in.  Since the managers email address is listed on multiple records the created case does not have the contact information populated.  Just to recap the managers email address is listed on the managers actual contact record in the EMAIL field.  It is also listed on a lot of other contacts as the managerEmail__c field.  

  So in summation, I would like to know if anyone knows of a way to have email-to-case ignore custom fields and only look at the standard EMAIL field on the contact object?

Any help would be greatly appreciated!