How to make some extensions private to another group of extensions

Hi,

I got a request to make some extensions private to some extensions group.
I explain:
Boss and managers extensions does not want to receive internal calls directly from employees, just thru their secretaries. But they want to receive internal calls from managers and they want to be able to call any extension.

Is there a way to do that with FreePBX ?

Thanks in advance.

you can use the unsupported module custom context and create a different context for your normal versus super users.