[rails3] DRYing up repeating routes for several models

Question

Hello, I have some models like News and Downloads which have_many comments :as => :commentable. Comment belongs_to :commentable and is :polymorphic. Like the comments, there are subscriptions. So my routes look like this:

resources :news do
  resources :comments do
    post :like, :on => :member
    delete :like, :on => :member
  end
  resources :subscriptions
  ...
end

resources :downloads do
  resources :comments do
    post :like, :on => :member
    delete :like, :on => :member
  end
  resources :subscriptions
  ...
end

...

Is there a way to DRY this up? I tried defining

def comment_resources
  resources :comments do
    # ...
  end
  resources :subscriptions
end

at then top of routes.rb and then calling comment_resources but it seems dirty to me because it isn't namespaced / in a class correctly.