How to differentiate routes by the paths?

Question

Here's the situation I'm having.

1. host.com --> backend A
2. host.com/path/id --> backend B

If the url contains only the base url then map the request to the A. Otherwise, if the url has path with id then B.

This is the rule for A, and it's working just fine.

Host: host.com

And this is the rule for B

PathPrefix:/path/{id: [A-Za-z0-9-]+ }
Host: host.com

I've changed tried and PathStripRegex, but I keep getting 404.

Thanks for helping