"Bump" selected topics in subcategories to display in the higher-level category?

I have an Announcements category, with several subcategories for more specific areas. Some of the more-specific topics might be kind of a firehose of posts, so I’d kind of like ‘No Subcategories’ to be the default list filter. But sometimes, I’d like to highlight something from a subcategory in the main list — and I don’t want to duplicate it. Is there a way to make it so selected (via a tag, number of likes, current pinned state?) posts “rise up”?