Istio ext auth with custom authorization policy - ext auth as a http microservice API

We want to integrate a external authorization htto microservice with istio using custom auth policy.
I am following this docuemntation: Istio / External Authorization

However, it looks like when we do the global mesh configuration we provide the service name and port. But in our use case we need to call a specific API endopoint of the http microservice for external auth like (/auth/authorize). I dont see any option here to provide the endpoint path. However I see this can be done using older approach using envoy filter and lua scripting. My question is can we use a microservice AP as a external auth in the new approach of ext_auth ( custom authorization with mesh configuration). If yes, can you please direct me to the relevant documentation?

Note : I have seen pathPrefix paramaeter in the global mesh config documentation, however it is not clear how it can be used to send request to a specifc endpoint of authorization server ( if at all it is related to that) . I have tried the same in mesh config, but failed to get it work

Hello, PLease let us know if anyone has any idea on this