Nesting a singular resource

I have two resources in my routes.rb;

map.resource :people, :controller => :people do |people|   people.resource :a_to_z, :controller => :people_a_to_z end

map.resources :groups do |groups|   groups.resource :a_to_z, :controller => :groups_a_to_z end

'People' is a singular resource, and 'Groups' are resources. This means that the people_a_to_z works just fine with the url of people/a_to_z, but the groups_a_to_z doesn't work because the routes.rb is expecting a groups/:id/a_to_z. Is there any way that I can get the a_to_z to work with my groups in the same way that it does with people?

p.s. the People resource is there to take a task away from a Users controller, therefore making the URLs look more in line with navigational conventions. I could've chosen People / Person naming from the offset, but I chose User because of all the tutorials and plugins I'm using for my learning; 'User' seems to standard naming convention.