As a temporary workaround, I was able to achieve my desired choices by:
- filtering the query args
- running my own query within the filter callback
- preprocess and select my desired choices
- return modified args with my desired post_ids set in the
$args['post__in'] and $args['posts_per_page'] = count($args[post__in])
This is of course inefficient as it will take those arguments and query again for them, but it works for now!
