Multiple calendar permission in iCal Server

I’ve having trouble finding the answer online and was hoping someone on AFP had a solution for this.

If a user on the Apple Server has multiple calendars, there doesn’t seem to be a way to delegate administration of one calendar, but not another.

For example:

John has two calendars, Work and Personal.
John wants to delegate Read/Write of "Work" to Anna, his assistant.
John does not want Anna to see his Personal calendar.

Is this possible to accomplish while still keeping all the calendars on the server?