Shared calendar appears as UUID

Hi all,

To have "Vacation and Out-of-office" and "Staff Events" calendars in our organization, I have done the following:

- created an account called events@ourdomain.org

- created the calendars as that user

- shared the calendars (in Calendar.app) to the group all Local Network Users are a member of ("Workgroup")

This seemed to be working sometimes, but not anymore. Now, when new users are added to the calendar server and add their accounts to their computer, Calendar.app invites them to subscribe either to: calendars with no name (...Join calendar " "? Shared by events) or the UUID (...Join calendar 57c6c24e-c7f5-4d31-9f8c-58ddd7f35b82? Shared by events)

How can I make this better? Users seeing these kinds of messages are delaying adoption of the calendar service in our organization and making me uncertain that OS X Server is the correct product for us.

Thanks