Customizing REST calls.

Hi!
   Can we customize a map.resources call so that it calls different
methods based on the HTTP verb called?

Like:

map.resources :posts, :controller => 'admin/blogs'

Would call the

Admin::Blogs#index() on GET
Admin::Blogs#create on POST
Admin::Blogs#update() on PUT
Admin::Blogs#destroy() on DELETE

But I want that on GET method, instead of calling the
Admin::Blogs#index() method, it should call the
Admin::Blogs#list_posts method. How can I customize that? I know that
i can user the :member and :collection modifiers that can provide
additional operations on resources but that's not the way to go.

Regards,
Mohsin