Use a bridged call appearance to the CA on the secretary's phone.
DDI calls to the boss will appear on the boss's CA
Train the boss to grab a bridged appearance instead of a CA when making calls internally. Calls will then appear to be from the secretary.
As tom and riddle have said - you are trying to find a technological solution to a HR issue. Train the staff correctly and then enforce the, quite frankly, stupid policy using company disciplinary procedures
Take Care
Matt
I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone.