Mail / Calendar split access

Do you know if it is possible to split access between mail and calendar?

I have a user who wants to give someone full access to her emails (Read/write/Edit etc) but not to her Calendar. She would like to be able to put in private calendar entries and not have the user with mail access seeing it.

At the moment it seems to be an All or nothing setting. Is there an agent that can be set up for access?

Subject: Nope

The way the delegation model works is from cal on up so if you give mail access it gives cal access. They owner can mark the entries private and that will work,

Subject: …

Have tried that, but even if the owner marks the entry as private, anyone with full email access can view it.