So with HTTP requests you can see the domain name in the header and forward it to the correct host. That was never a thing you could do with SSH, does this allow that to work?
replies(3):
Host *.internal.example.com
ProxyCommand ssh -q -W %h:%p hop.internal.example.com
in the SSH client config would make everything in that domain hop over that hop server. It's one extra connection - but with everything correctly configured that should be barely noticeable. Auth is also proxied through. ssh -J hop.internal.example.com foo.internal.example.com