You can get the effect you're looking for by using the alwaysCreate property - more info on this property can be found in http://www.tersus.com/#Id=981.
If you set the alwaysCreate property of your Page to false, then Page will not appear until it (or any of the elements in it) are updated by another model explicitly. In your case the process model which validates the login should on success, create Page or update some child element of it. Similar behavior (though regarding another display template) is discussed in http://www.tersus.com/#Id=5652.
For best results, use the Firefox browser..