Ember simple auth 1.0. custom authenticator

There is one problem,

I want to set the routeIfAlreadyAuthenticated route in environment as the route with dynamic segment(/:userid/dashboard) which is based on the logged-in user.

How can i do that?

//config/environment.js
  ENV['ember-simple-auth'] = {
    authorizer: 'authorizer:custom',

    routeAfterAuthentication: '/dashboard',
    routeIfAlreadyAuthenticated: '/dashboard'
  };