drupal 8: how do i override the template of a region for a specific route?

I need to override a region only for a specific route. There doesnt seem to be a file-naming convention for this.

If

page--myroute.html.twig overrides the entire page at “/myroute” and region--myregion.html.twig overrides all myregion on every page

I need to combine them into something like:

page--myroute--region--myregion.html.twig 

This way of filtering by filename could be very useful. Does Drupal support that?

Thanks