Default Area Code on Contacts in Citrix Environment

I support remote users that access Outlook 2003 via Citrix running on a
Windows 2000 Terminal Server. The remote users are located in
different cities and therefore have different area codes. When they
type a 7-digit phone number into an Outlook contact it defaults to the
area code setup in the dialing rules in Control Panel which is not
their local area code. Is there anyway to get Outlook to use a
different default area code on a per user basis?

Thanks!

Jeff