Ember ember-simple-auth override routeIfAlreadyAuthenticated in application route

How do you override the routeIfAlreadyAuthenticated?

And once that happens, how can it transition to a route with a dynamic segment?

I realize I can override sessionAuthenticated; and in that ways override the functionality of routeAfterAuthentication. However, routeIfAlreadyAuthenticated is a computed property that is executed in a beforeModel in the unauthenticated-route-mixin.js mixin.

Any help would be greatly appreciated.