Nick Gravelyn:You probably won't get much support here since you are trying to workaround the LIVE networking feature. You might ask over at GameDev or the Hamachi site, but I highly doubt you'll find any response from a Microsoft employee on how to do this.
As for me personally, I don't know either. Sorry.
I wouldn't say he's really trying to work around anything, having two network adapters, both with valid IP addresses isn't an uncommon situation, and ensuring that G4WL uses the right network adapter is rather useful. I too have tried using Hamachi though, and followed the article on the Microsoft website on how to prioritise one adapter over another (changing it's priority) but it had no effect, contrary to what the Microsoft website said.
Unfortunately though, I too had the same problem, and the only workaround was to disable the adapter I didn't want, start the game, then reenable, but it never actually worked properly.