The OOB templates to display KA's is not editable. So it's not possible to change what is displayed to whom via Liquid. The OOB template is therefore show/hide everything. A liquid template for KA's that controls the content would be helpful in that it would allow the rendering of the content block, plus any other custom fields - based on the web roles of the logged in user. We could have some finesse with what is displayed. Also the OOB KA search doesn't allow adding of filters. If I add custom fields to the KA to define a type of article or some other custom categorization, the OOB search will not allow a filter to be added for this - which limits it's usability.