I tend to use the same approach as sarond, setup an ARS where you dial 0 XXXX XXXX will show number and 0* XXXX XXXX will hide the number
But if this is not acceptable, what you could do is use an ARS list, the first option shows the number using your current route, then the second one uses a new set of routes that uses the carrier code to hide your number. You then setup COR to block the boss from the first route and everyone else from the second router. More work and you need to be confident with ARS/COR programming, but should work.
The carrier code to hide the number is not the FAC (*45) it will be something else, check with your carrier (you could try 1831 as it is a common code used)