渴望从Rails中的关联加载named_scope

有没有办法从关联中急切加载named_scope？

我有我的文章模型:

class Article < ActiveRecord::Base
  has_many :comments
end

和我的评论模型:

class Comment < ActiveRecord::Base
  belongs_to :article

  named_scope :approved, :conditions => { :approved => true }
  named_scope :unapproved, :conditions => { :approved => false }
end

我可以急切地加载文章的所有评论:

@article = Article.find(params[:id], :include => :comments)

我怎样才能这样做,但仅限于批准的评论？