Using Distribution Group as Delegate

[Marr Jones & Wang]

We have created a dummy secretary in Outlook and we use her calendar as the
conference room log. When new employees start, we need to give them delegate
rights to that calendar. To save time and effort, we started giving delegate
rights to a Distribution Group (rather than to individuals), but when new
employees start and are added to the Distribution Group in Active Directory,
that doesn't seem to allow the new employee to access the calendar. We still
have to log on as the dummy secretary and reset the permissions. (We just
remove the group then add it again). Are we doing something wrong? How can
we set it up so that new employees added to the group then have delegate
rights?

Thanks for your help!