How to handle redirects with additional segments before locale?

[Maclay74]

Hello.

I'm working on a website that needs to have a region segment before locale and handle redirects accordingly.
Like /page or /en/page/ should lead to /us/en/page.

It might work with new custom prefixes, but the problem is, we get region from the web server, so.. we need to somehow set the correct one. Moreover, region doesn't affect our language, we can have /es/es-mx (don't ask, I know, I know).

So, how should I handle redirects in this case? I am looking at this docs section but can't figure out how to handle it in links, for example.