Groups inside of groups?

It doesn’t seem like I can put a group of layers inside a different group. I like to organise my layers into masks and tracks. In my current project I have 3 distinguished gentlemen that I will be rotoscoping out, and would love to have seperate groups for each subject and then inside that group have my masks and tracks for that subject. Just to be extra organised, especially on projects with lots of layers needed.

I’m wondering if this is already a feature, and I’m missing it? Or if this is a feature we could see in the future? I understand that the order of layers in groups determines which layers are on top, so maybe this provides some difficulties?