Visualisation of boards/cards for "flight levels"

As a big fan of planning scenarios with KanBo (portfolio/program/ressouce management etc.) I would like to suggest that one could visualize whether a board is a "higher flight level".

This could mean:

- a higher-level board - like a program-board - can be marked with e.g. a border/frame

- also cards within a higher-level board (representing e.g. a project-board from a "lower flight level") can be marked with a border/frame or an icon

Board Collections are a great way of structuring "flight levels" and even relations. But within boards and cards the visual differentiation of the dimensions like flight levels would be a great help for the understanding. Especially for users who join the context rarely or recent.

Or is something planned with a board releationship-visualization?