It may be desirable to impose limitations or restrictions on what Collections of Knowledge a specific role (Self Service for example) can access.
Go to Configure Application > Users and Permissions > Roles and Permissions > SelfService.
Open the "Object Permissions" tab, and select "201-250 FRS_IPCM..." from the drop-down. In the menu, across from "FRS_Knowledge" click on the second "Edit" (Access column).
From here, you can define a case to limit the search results returned to only a specific collection. For example, the following will limit Self Service to only see Knowledge articles in the "Customer Knowledge" collection: