I'd like to thank one of our readers, Hamid, for sharing an update of sorts to the scene file I posted for tutorial #2. It has a pretty handy way of adding more and more objects to create the collision light up effect. You can find the file here.
Give it a spin and I hope it helps you out! You no longer would need to duplicate the Xpresso tag for every object that you want to collide and light up. Just duplicate the materials.