groups and forward and back.

This is such a basic question and I’ve been using toon boom harmony for ages but never solved.

“Character A” is grouped.
“Character B” is grouped.

I want parts of “character A” to be in front of “Character B” and parts of “character A” to be behind “Character B” (and vice-versa)
(please see picture, my picture as an example)

The only way I’ve been able to make this work is putting the both characters in the same group. But I don’t want to do this.

I want to keep them in separate groups.

I’m sure there are millions of tutorials on this but I don’t know what to type in google!

Thanks in advance

Change your composites inside your groups from bitmap to passthru, then you’ll be able to nudge individual body parts behind/in front.