Have you considered using the same Proxy or VPN? I work remotely and sometimes access services through a VPN based in the country my coworkers are at specifically to avoid this kind of annoyance.
This is a great idea, although the boss is pretty technically challenged so getting him set up on it might be interesting. It's been extremely difficult just to teach him to use LastPass.
There are also a number of browser extensions which may be easier to set up and use for non-technical folks, for example FoxyProxy seems to offer one. I've never tried any myself, though.
