When subitem is done, move subitem to done

I want to move a done subitem to the done group on my board. In automations, it looks like I can only move the entire item, not just individual subitems. Thanks for your help.

This is very much needed!
When I’ve change a subitem status to Done I would like it to move to the “Done” group. This is what I do with items so that I can see they now have a “Done” color in the Timeline. Is it possible to do the same with done subitems and move them to the “Done” group so that the will have different color on the timeline?
Thanks a lot for the help.