For this to work, the Exchange server needs to be on SP3.
This wil make it so that when a user clicks on the address book in Outlook, they are presented with their local address book, not the GAL.
Set-CASMailbox -Identity Rich -ShowGalAsDefaultView $false
If you wanted to apply this to all users you could run:
Get-Mailbox -RecipietType UserMailbox | Set-CASMailbox -ShowGalAsDefaultView $false