Can I control access to an users Exchange calendar from the server?

We have numerous users here with MS Exchange 2003 mailboxes with a calendar etc. The problem I have is that I wish users to have rights to view and possibly edit/add items in each others calendars.

The only way I have seen how to do this is for each user in question to go into their own calendar permissions and add the users who need access to the list of users, and give them the necessary rights (Author, Editor etc).

Is there a way I can control all of this from the server? It would be much quicker and easier to manage if I could. All I can find in Active Directory is the “Mailbox Rights” option under “Exchange Advanced” in the user properties.

Am I making sense?

Thanks