nester routes issue

This is a snippet of my routes.rb file

map.resources :users do |users|
    users.resources :blogs do |blogs|
      blogs.resources :articles do |articles|
        articles.resources :comments
      end
      blogs.resources :comments
    end
  end

Just wondering if it is possible to have the comment model in 2
different places. From the snippet code, a blog can have comments.
it is also possible for articles to have comments as well. I'm just
wondering if there is an easy way to handle this since I will have a
very complicated comments_controller. The comments_controller will
have to determine where it is comming from, either through users/blogs/
articles/comments or user/blog/comment.

Let me know if there is an easier way of doing this.

Thank you.