Using a contact list from a different outlook mailbox

A user has a group email set up using a dummy AD account.
User are then given access the to mailbox created.
Is it possible to add the contacts list from the second mailbox to the address box option, when sending mail on behalf of the second mailbox.
Opening the contact list only show the contact from the primary mailbox.
It can be done using a PST but as the contacts list is altered daily would prefer the ability to just link to the list and use it.