Google cloud load balancer: Redirect host and add base path while keeping the remaining path intact

Question

I want to redirect the host of my incoming url and add a base path to it. Using the pathRedirect rule helps me achieve this, but it strips out any original path original url had.

abc.mydomain.com/original/path should redirect to

abc.mydomain2.com/base_path/original/path

I tried adding a pathRedirect rule but it will just redirect to that specific path, stripping any original path the url had.