Create user groups that provide access to selected knowledge bases and assign them to users.
When you have multiple knowledge bases (KBs) and content managers, you may want to restrict users to have access to those KBs that are relevant for their daily work. For example, your organization may support multiple languages or products, where a each language or product has its own KB and is curated by a specific content manager. In this case, you can create a user group and assign a KB to that group. Then you can add users to the same group.
Your users are now limited to access the selected knowledge bases only.