Private Article Links for Knowledge Base

We would like the ability to be able to set a knowledge article to private, and have it only be accessible via URL.
This would help us create private articles that would be in use for specific workflows when a customer needs them. For example,

Currently, the only access controls are Public, Access group (membership required) and SSO. A private category should be included here, one with the ability to make that article accessible via URL for anyone with the right link.