Dark theme - Nested cards - Darken card background with elevation as per Material Design Dark Theme

I would like to have the ability to group cards by nesting with the theme using background transparency to determine the background color. Hence background shade indicates group elevation/depth.

I may not have worded this correctly. But what I would like is the ability to group cards as done by Material Design Dark Theme " Higher elevation, lighter surface" found here. See “surface overlay values”.

I’m thinking of a group card that provides context (a title) and applies a transparency (of white) to provide a background shade that reflects depth.

I believe this will enable me to group some of my dashboard cards better.