Auto Complete - Outlook 2010 - Change from first to last name

Hello,

We recently migrated from a Novell eDirectory/Groupwise infrastructure to AD/Exchange.

In Groupwise, autocomplete of email addresses was by Last Name.  Following our migration, and in Outlook, it pulls the autocomplete data by first name.

Without getting crazy, is there a way to change Outlook auto-complete to pull from Last Name rather than first?  Is there a "free" add-in we can share with our users that would allow this? 

Thanks.