Extending Category Filtering for Custom Module

Is there a way to extend the way that filtering using a category widget works?
I have used Gabe's webinar to create a custom module and some custom categories.
No i dragged the categories widget onto my page as well as the custom module widget.
I have edited the Taxonomyid and the Fieldname properties in the category widget so that it filters with my custom module. This works well.
However my category is a hierarchical category type. Basically continents and countries.
Yet in the widget i only see the countries. What i need is to also see the continents. 
So that if i click on the continents all items under all countries on that continent are shown. But when i click on the specific country then only the items for that country are shown.

Is this possible to do without rewriting both the categories widget and the custom module widget?

Also, what if i wanted to write a new widget to replace the categories one, how can i then make sure that when i click on an item the information is passed to the custom module widget?

Basically i need to know if there is a way to extend any of the functionality here without replacing both the controls.