I've cheated it in the past, shooting the scene twice and mixing the frame in post. Works best if you have a vertical object like a doorframe to split the frame to.
Split diopter, 2 plate shot, Or be selective with your background subject placement and select an f stop and lighting which allows both subjects to be in focus. Watch Citizen Kane for ideas.
Hi i alszo would like to do this shot. Excuse my ignorance but what do you mean by roto the foreground? And can i use any lens or is there a split lens or something i can purchase? I love the use of this type of shot, especially in de palma films