The closest thing to what you want is here [url=http://www.filetransit.com/view.php?id=11194]MidPoint Plus 6-User Edition 5.04 - Sets a new standard for Internet Sharing. With one simple software installation,...[/url] Atleast the closest one I know of.
There is another teaming software I cant remember the name now and couldnt find it on google either may be hidden deep in the results somewhere can do exactly what you are looking for so it would be well worth checking on Google with keyword "teaming software"
I will give it another try when I am not drunk will have better luck with lesser alcohol in my blood