I was wondering if it's possible to set the failure_app per scope.

This is my current setup:

Rails.application.config.middleware.use Warden::Manager do |config|
  config.failure_app = lambda { |env| SessionsController.action(:new).call(env) }
  config.default_scope = :user

  config.scope_defaults :backend,   strategies: [:password], store: true, action: :backend_new
  config.scope_defaults :frontend,  strategies: [:password], store: true, action: :frontend_new

end

However, keeping everything REST-ful and since the scenario's of logging in from the backend or the frontend differ a lot, I'd rather be able to set the failure app to Backend::SessionsController.action(:new) for one scope, and Frontend::SessionsController.action(:new) for the other.

Is this possible, and if not, is there a reason for this, am I trying to solve this problem the wrong way?