Contacts delegation allows users to delegate full access to the contacts in their “My Contacts” group without granting access to their mail or anything else in their accounts.

You may delegate your contacts only to other users within your domain. Like mail delegation, you may delegate your contacts to no more than 25 other users at the same time. Delegation allows the sharing of the entire “My Contacts” list only. You cannot delegate a subset of your “My Contacts” or delegate contacts not in your “My Contacts.”

How to access what’s new:
– Navigate to www.google.com/contacts
– The “More” menu now has a “Manage delegation settings” option

For more information:
http://support.google.com/a/bin/answer.py?hl=en&topic=20016&answer=2590392