The solution might be available in Rls 10.1 or 11 of IP Office. Accordingly, to the road map the following feature will be introduced.
“User Button / Pickup Privacy
Ability to prevent users from monitoring status or picking up calls for specific other users (e.g. privacy protection for senior management, Workers Council members)”
Check out the TechTalk for additional information about the IP Office roadmap.
https://sales.avaya.com/documents/1399647589404