I'm using labels like folders/categories. For example, I have this hierachy for some lables

"Coding->project name -> priority high"

"Coding->project name -> priority medium"

"Coding->project name -> priority low"

When I attach one of the priority labels, I want missive to auto-add its parent labels as well. I'm currently accomplishing this with a bunch of rules but it would be nice if there was built in functionality for this.