Merge Contacts

[prairiewind via OfficeKB.com]

I have an Access file that has over 500 contacts in it. Several times a year,
I want to send this information to multiple users across the nation. They
already have these contacts in Outlook. What I'm looking to do is find a way
that they can override the existing contact with the new contact information.
There is already a duplicate contact finder in Outlook, but that uses the
"File As" field as the comparison. My issue with that is the names often
change (married so last name changes, death of spouse, etc.).

Things I'm looking for as options:
1) VBA code or macro that would compare a specified field (I have unique
contact ID in a field for this) and update just like the existing duplicate
contact finder instead of the "File As" field.
2) Program that would do this. I don't want close to 50 people have to pay
for a program is I can help it.
3) Any other suggestions/ideas.

I can either send the contacts to the other users as an Excel file, Access
file, .pst file and have them import into a temporary folder and then merge,
or basically any other way possible.

I am using Access 2007, Outlook 2007, Windows XP.

I've inquired on an Access forum and no answer, so thought I'd try here as
well.

Thanks,
Jeff