If you have company contacts, best to put them in a public contacts folder,
really - set permissions as you need them. Everyone can add that PF as an
address book in outlook if they wish.
If you still want to try using another person's folder, here's how:
1. Start with a profile that logs directly onto the other user's mailbox,
not your own. You'll need to have full rights to that mailbox in order to do
this...set on the server, not in the client. This may grant more permissions
than you want, note - including send as rights.
2. On the Properties dialog for the other user's Contacts folder, make sure
that it's set to display in the Outlook Address Book and give it a display
name other than contacts, such as Joe's Contacts.
3. Close Outlook.
4. In Control Panel | Mail, edit the *same profile* to change the mailbox
from the other user's to your own. On the Advanced tab of the Exchange
Server service, add the other user's mailbox as a secondary mailbox.
5. Restart Outlook, and you should see the Joe's Contacts in your Outlook
Address Book as well as your own Contacts folder.