Breaking ruby module across several files

I have a ruby module that is supposed to wrap up quite a few classes

module A
  class First
    #somemethods
  end

  class Second
    #somemethods
  end

  class Third
    #somemethods
  end
end

What i would like to do in rails is to break up these classes into several files what might be the best practice to split this huge module into several relevant files?