The best way, I think, would be to create an override function like the book plugin, then check for !qa_request. If !qa_request, qa_redirect('hot');
I haven't tested that, but an easier way is to just add this to your layer:
function doctype() {
if(!$this->request)
qa_redirect('hot');
...
The problem is this means the qa_content has to be created before it gets to the redirect.