Is it possible to add support for package name scope prefix started with $ or #?

[JustFly1984]

I’m building an alternative registry to npmjs.com.

currently we have ability to publish public and private packages to npmjs.com with @ prefix. For example I’m maintaining @react-google-maps/api package.

im looking to separate packages deployed to my registry with prefix $. To signify it is a commercial licensed package. I want my registry to be fully compatible with all npm tooling, though I’m only interested to host commercial licensed packages in my marketplace. For example, I want to release a new version of my package in my registry with new package name $react-google-maps/api, and be able to use it together with other npm packages in package.json, allow my package to be used as dependency of other packages or projects without conflicts with main npmjs.com registry published packages.

Is it possible to add third level namespaces?
For example @ospn/react-google-maps/api

is it possible to use pnpm with $ prefixed packages?
How much effort it could involve to add my registry to supported by yarn?

Thank you for great project.