Use https-portal as a proxy for host running directly on the host outside docker

[damascene]

Is it possible to have a domain that is connected to a port in the host instead of a docker container?

Example:

https-portal:
  # ...
  environment:
    DOMAINS: 'wordpress.example.com -> http://wordpress:80, another_domain.example.com -> http://127.0.0.1:8118'

So the second domain would be an app running on the host machine. I saw some suggestions to use host.docker.internal but it didn't work in my case.

Any suggestions please?