Comment We wrote an app to handle a similar situation (Score 1) 264
We wrote a little app that runs on startup on our laptops. It basically does an IPConfig /all to a txt file, then parses that looking for our internal domain(s). If it doesn't find it, it sets up things one way. If it does find it, it sets them up another way. In our case, we used it to set the proxy and the speed/duplex on the network cards. But I'm sure you could use it to set different DNS servers.
Hope this helps,
TD