[horde] Calendar Sharing

[guido at lorenzutti.com.ar]

Hi People: I have the following problem with turba, every user can create
a calendar and share it to everyone. So I have users that create a
calendar like:

"everyone is stupid" and share the calendar with all the users and change
the owner.

Is there any way to prevent the change of the owner of the calendar? At
least this would let us know who create the calendar.

The best thing would be a permission to allow only the administrator to
create calendars and assing owners, and another privilege to allow only
the owner to assing participants in the calendar.

Any ideas would be great. Thanks in advance.