How to call global function on route change within Durandal?

Given the following scenario for our Durandal application:

When a customer visits certain URL's of our SPA we would like to present him a dialog/pop-up. For the initial load this is not a problem, we call a function from the activate callback function in the shell.js.

The problem is when the user navigates through our site and reaches a certain URL where the dialog should pop up.

Let say we've two viewmodels product and prodcutOverview and the shell. All three would have an activate function like this:

vm.activate = function () {
    var keywordsExists = checkUrl();
    if(keywordsExists){
       globals.showDialog();
    }
};

The idea of globals comes from this question

How do I create one activate function that is used on every route change so I prevent the duplicate code on my viewmodels?

You could create the common activate function as a require module and then reuse it in that manner.

define('common-activate', ['globals'], function(globals){
   function checkUrl(){
      //checks url
   }
   var activate = function(){
      var keywordsExists = checkUrl();
      if(keywordsExists){
      globals.showDialog();
   }
   return activate;
}

define('products', ['common-activate'], function(activate){
   return {
      activate: activate
   };
}

define('productOverview', ['common-activate'], function(activate){
   return {
      activate: activate
   };
}