It is possible to add a navigation link to the parent portal for different news categories, but it is not possible to display only the latest news stories or latest documentation for that particular category. When you show only one news category on a tab, this shows the latest news and latest documentation for all news categories that have been configured in the system. If possible, when a navigation link is used for only one news category, only the latest documents and stories associated to that news category should display within the same tab.
