Hey Doug,
You are right, the interaction itself will not highlight the button or the image. What you are looking for is a styling code, which can be written in countless ways. Basically, you apply one style to the control that was just clicked, and another to all the other controls.
In this specific sample, we used updateOpacity and set it to true for the clicked group of controls. For example, the Asia group has this script on the click action:
hospitality.updateOpacity("AsiaGroup", true);
hospitality.updateOpacity("NorthAmericaGroup");
hospitality.updateOpacity("EuropeGroup");
hospitality.updateOpacity("OtherGroup");