Internal registryDependencies feature

[JeremiahSecrist]

At present understanding the only way i can make interdependent items on my registry is to do something like:

{
      "registryDependencies": [
        "https://myownregistry.example.com/r/icon.json"
      ],
}

this is quite cumbersome when trying to build a complex tree that may move domains over time.
can we add an @self:icon style mechanism for internal referencing? of which gets replaced with a local url?