nested resource routing

I am using rails 1.2.6 and I'm trying to define a RESTified route that will work for a nested resource. I have a permission resource that I want to be nested into all my other resources. If I wanted to nest permission specifically for say my customer resource then that would simply be:

map.resources :customers do |customer| customer.resources :permissions end

and this will give me url methods such as permissions_url(@customer), permission_url(@customer, :permission_id) etc.

However what I want to achieve is a generic route definition that will give me this functionality across all my resources. Something possibly looking like:

map.resources :any do |any| any.resources :permissions end

where any can be any resource and have url methods like permissions_url(@books), permission_url(@itineraries, :permission_id).

Any ideas will be appreaciated. Thanks.