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.
>>pagnol+(OP)
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.
>>freedo+PQ1
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.