there is no easy way to do this while maintaining administration through the web client. The way we do it is we have an account that stores company calendars say
calendars@domain.com then we have a calendar called /Company that is shared read access to the whole domain.
We then have a script to create new users. The script first calls zmprov to create the user, then zmmailbox to mount the shared calendar to thier account. The script also sets up various other shared resources automatically. This can't be done via the web admin tool.
See the wiki pages for
zmprov and
zmmailbox