Search and add contacts from a network directory service
If your Mac is set up to access network directory services—for example, at school or work—they’re shown in the Contacts sidebar.
Note: Contacts in a directory service appear only when you search the directory. Make sure you’re connected to the server where the directory is located; otherwise, results aren’t shown. (An offline Exchange account is indicated by a lightning bolt icon 
.)
Search a directory service for contacts: Select a directory in the sidebar, then search for a contact. The Exchange server limits results to 100 contacts.
Add a contact from a directory service to a group: Drag the contact to any group in the sidebar that’s not a directory service.
You can’t print contact information directly from a network directory service. You must first drag the contacts into another account, then print their information.