## initializers/setup_user_groups.rb
USER_GROUP_TYPES = %w{group ministry}
USER_GROUP_SUB_RESOURCES = %w{page user}

## routes.rb (excerpt)
  USER_GROUP_TYPES.each do |resource_type|
    map.resources resource_type.pluralize, :controller => 'user_groups' do |groups|
      USER_GROUP_SUB_RESOURCES.each do |subresource|
        groups.resources subresource.pluralize
      end
    end
  end

## application_controller.rb (excerpt)
  before_filter :fix_user_group_sub_resources

private
  def fix_user_group_sub_resources
    USER_GROUP_TYPES.map{|t|"#{t}_id".to_sym}.each do |resource_id|
      params[:user_group_id] ||= params.delete(resource_id)
    end
  end


## user_groups_controller.rb (excerpt)
class UserGroupsController < ApplicationController
  def index
    @user_groups = UserGroup.all(:conditions => ['group_type = ?', extract_group_type_from_url])
  end

  def new
    @user_group = UserGroup.new(:group_type => extract_group_type_from_url)
  end

  def create
    @user_group = UserGroup.new(params[:user_group].merge(:group_type => extract_group_type_from_url))
    #...standard save stuff...
  end

protected
  def extract_groups_type_from_url
    routes = ActionController::Routing::Routes.routes_for_controller_and_action_and_keys(controller_name, 'index', nil)
    segments = ActionController::Routing::Routes.to_plain_segments(request.path)
    route_segments = routes.map do |route|
      route.segments.select{|s|s.respond_to?('value')}.map{|s|s.value}
    end.flatten
    (route_segments & segments).first
  end

  def extract_group_type_from_url
    extract_groups_type_from_url.singularize
  end
  helper_method :extract_groups_type_from_url, :extract_group_type_from_url
end

## user_groups_helper.rb
module UserGroupsHelper
  def user_groups_url
    send("#{extract_groups_type_from_url}_url")
  end

  def user_groups_path
    send("#{extract_groups_type_from_url}_path")
  end

  def user_group_path(user_group)
    send("#{user_group.group_type}_path", user_group)
  end

  def edit_user_group_path(user_group)
    send("edit_#{user_group.group_type}_path", user_group)
  end

  def new_user_group_path
    send("new_#{extract_group_type_from_url}_path")
  end

  USER_GROUP_SUB_RESOURCES.each do |sub_resource_type|
    define_method("user_group_#{sub_resource_type.pluralize}_path") do |parent_resource|
      send("#{parent_resource.group_type}_#{sub_resource_type.pluralize}_path", parent_resource)
    end

    define_method("user_group_#{sub_resource_type}_path") do |parent_resource, sub_resource|
      send("#{parent_resource.group_type}_#{sub_resource_type}_path", parent_resource, sub_resource)
    end

    define_method("edit_user_group_#{sub_resource_type}_path") do |parent_resource, sub_resource|
      send("edit_#{parent_resource.group_type}_#{sub_resource_type}_path", parent_resource, sub_resource)
    end

    define_method("new_user_group_#{sub_resource_type}_path") do |parent_resource|
      send("new_#{parent_resource.group_type}_#{sub_resource_type}_path", parent_resource)
    end
  end
end