@CZFan: This one is on him, I gave him all credit (or let’s call it disclaimer). Not that the whole thing would be rocket science, it’s relatively simple idea, when you look at it after someone else comes up with it. But somehow it still makes even my brain go in loops. 
@611: You can mention to support, that the thing you desperately need is conditional DNS forwarding. And that it’s really important, the proof of that being the thing you’re trying to do now. Maybe you don’t mind, but regular people should not be forced to such desperate measures. It’s not just one hack, it’s two hacks combined and it still has shortcomings.