如何从下游对象的子集中获取复杂活动记录has_many的列表

当在中间的关系上实现多个外键时,我很难从分层父关系中获取所涉及的游戏列表.

鉴于League Object NFC,找到它的所有Game对象[G1,G3,G4]

#  id           :integer          not null, primary key
#  name         :string
class League
  has_many :teams
  # has_many :games, :through => :teams (Is there some way to do this?)
end

#  id         :integer          not null, primary key
#  team_name    :string
#  league_id :integer
class Team
  belongs_to :league
  has_many :home_games, :foreign_key => team_a_id, :source => :game
  has_many :away_games, :foreign_key => team_b_id, :source => :game
end

#  id                   :integer          not null, primary key
#  game_name            :string
#  team_a_id :integer          not null
#  team_b_id :integer          not null
class Game
  belongs_to :home_team, :class_name => Team
  belongs_to :away_team, :class_name => Team
end

LEAGUE - TEAM - GAME 
---------------------------------
AFC - 
        PATRIOTS - 
                 Home       Away   
               G1(PATRIOTS vs DALLAS)
               G2(PATRIOTS vs PITTSBURG)
        PITTSBURG - 
               G2(PATRIOTS vs PITTSBURG)
NFC - 
        DALLAS - 
               G1(PATRIOTS vs DALLAS)
               G3(DALLAS vs GREENBAY)
               G4(DALLAS vs SEATTLE)
        GREENBAY
               G3(DALLAS vs GREENBAY)
        SEATTLE
               G4(DALLAS vs SEATTLE)

nfc = League.where(name: 'NFC').first
# 
puts nfc.games 
##  array containing objects [G1,G2,G3]