Display object with subobjects when it's behind the wall

I have a character with hat or helmet. Also it can have a weapon in its hands. And me want to draw silhouette when character is behind the wall. For examle when I set material on character silhouette shows in hat or helmet. Also when I set this material on weapon, silhouette draws on character body. I would like to draw character and its clothes only on walls, and don't draw on itself.