Sign in to the Google Apps administrator control panel, selectSettings in the menu bar, then Contacts in the left nav menu

  • Under Contact Settings, select Enable contact sharing.
     
  • Specify which email addresses to include in the shared contact list:
    • Show all email addresses: Include both the primary email address and nicknames or alias addresses for users in the domain
       
    • Hide nicknames: Include only primary email addresses; aliases and nicknames are hidden
       
    • Hide the primary email address if the user has a nickname: Include a user’s manually entered nickname for all contacts; hide the user’s primary email address, aliases, and other user’s nicknames for the contact
       
  • Choose what is shown in the browsable directory in Contact Manager:
    • Show only domain profiles: Include profiles of users with accounts in your domain only.
       
    • Show only domain shared contacts: Include contacts added to the list using the Domain Shared Contacts API. They are people who don't have email addresses in your domain, but who your people need to be able to contact.
       
    • Show both domain profiles and domain shared contacts: Include both the aforementioned internal users and external contacts.
       
    Note that the name format (Last name, First name OR First name, Last name) of directory entries follows the name format setting in Gmail.