3/3 but its weak.
Susan and Nina have passing words in the hallway but its so brief you may miss it. ("I need to borrow your apartment." "Why do you need my apartment?" "Its just one of those things.") Also Nina has no other scenes and nothing to do with the story so its debatable if she is even a real character. More like a living prop.
Susan dies early in the movie, and the two have no conversation with each other.