Can we enhance the Artifact Registry module to allow Artifact Registries to be added to External Proxies in addition to Upstream Repositories?

Our use case is that we have an Artifact Registry for our internally published artifacts and an Upstream Proxy registry to proxy public packages from pypi.

We would like to create a single, central, registry that contains artifacts from both the pypi and our internal registry.

I understand I could add the pypi Upstream Proxy registry as an Upstream Proxy to our internal registry but my understanding is that will prevent me from being able to logically separate internal and public artifacts in Artifact Registry which is a requirement I have to maintain.