Routing.rb

namespace :admin do
  get :show do
    ...
  end
end

namespace :frontend do
 get :index do
   ...
 end
end

get :accounts do
 ...
end

map(:admin, :show).to("/my-admin/:id/show")
map(:frontend, :index).to("/")
map(:accounts).to("/show-me-my/accounts")

# or

map :admin do |namespace|
 namespace.map(:show).to("/my-admin/:id/show")
end

# and to use
link_to "Show Admin", admin_show_path(:id => 5)
link_to "FrontEnd",  frontend_index_path
link_to "Accounts", accounts_path
# or maybe
link_to "Show Admin", url_for(:admin, :show, :id => 5)
link_to "FrontEnd", url_for(:frontend)
link_to "Accounts", url_for(:accounts)