I do not see any situation that must have 'which', but these sound promising. I don't know if that is what you were looking for.
1.
Alex: "There are two people sitting there. One is the man you need."
Bob: "Which one?"
Alex: "The blue fellow which is across the exit." [which or that]
2.
Alex: "Your daughter married which of them? One that you liked best?" [only which]