MVC - Factor Repository Interfaces Based On Multi - Level Object Model?

I've got a multi level dependency chain in my object model: An organization has the following children relationships:

Organization
.CompetitionGroups
.CompetitionGroups.Venues
.CompetitionGroups.Competitions
.Divisions.Games
.Divisions.Games.Participants
.Divisions.Games.Participants.GameSegments
.Divisions.SubDivisions...
.Divisions
.Teams
.Teams.Players
.Teams.Participants
.Teams.Participants.GameSegments
.VenueDates

This is just a glimpse at the object model, but it's focused on the complexity of the relationships and lists. What I can't really get is what's the best way to factor my repository interfaces, given the requirements to do a unit of work. For example, to create a game, you'll need a venuedate and two participants. Does that mean the GamesController should require an IGameRepository, an IVenueDateRepository, and an IParticipant repository? Should they be rolled into one repository?

Also, what about in the consumption cases? For example, to display a signle team's schedule, you'll need all of the Participants for that Team, all of the Games for that participant, and all of the GameSegments for the participant. If those are factored into individual repositories I can't see how you can do efficient queries. Does that mean you have Repositories specifically focused on different cases? for example:

public interface IScheduleRepository {
public ICollection<Game> GetScheduleForTeam(Team team);
// More consumption methods
}
public class ScheduleRepositry : IScheduleRepository {
public ScheduleRepository (ModelContext context) {
// Do stuff with context
}
public ICollection<Game> GetScheduleForTeam(Team team) {
return (
from p in context.Participants
where ((p.Game.VenueDate != null) &&
(p.TeamId == team.Id))
orderby p.Game.VenueDate.StartTime
select p.Game).ToList();
}
// more consumption methods
}
public interface IGameRepository {
public void AddGame(Game game);
// More crud methods
}
// Not showing games repository
public class GamesController : Controller {
public GamesController (IGameRepository gamesRepo,
IVenueDateRepository venueDateRepo,
IParticipantRepository participantRepo) {
// do stuff with repos here
}
[HttpPost]
public ActionResult AddGame(Game game) {
// Skipping validation logic
// this?
VenueDate = venueDateRepo.Add(game.VenueDate);
foreach (Participant p in Game.Participants)
{
participantRepo.Add(p);
}
Game = gamesRepo.AddGame(game);
// or this?
// how would the game repo know to persist
// the children elements? is that tight coupling?
Game = gamesRepo.AddGame(game);
}
// more consumption methods
}

My question is I don't yet understand to what degree factoring your repositories make sense based on a connected object model. I'd love to get some advice here.