Off the top of my head, you might be able to see the host header after context variables have been extracted in the middleware request chain. Meaning they might be available in URL Rewrite and Post Auth.
So an additional header match for advanced URL rewrite or a custom plugin would do the trick.
However, I see preserve_host_header has been enabled in the API definition. so I am unsure what the result could be.
I would have to try this out.