It's been requested before:
KB Permissions for Users (Non Agents)
In my opinion, this is what this teammate is requesting as well:
KnowledgeBase Access - Need to be clear!
I would like to say again that:
This is a feature I would like to see as well.
If this could be based on Active Directory groups, that would be better.
Certain users would need access to advanced articles or would not need access to articles that do not pertain to their department.