I'm trying to use nodereference for Event management. There are Events, which contain Sessions. Sessions can be assigned Time-Slots and Rooms.

Sessions, Time Slots and Rooms are all related to an Event via node reference. But when I go to edit Time-Slots and Rooms in a Session, the options are not specific to an Event but show *all* Time-Slots and Rooms for all available events. I'm trying to find a solution that would allow Time-Slots and Rooms to show only related to a specific Event. Is this possible?