How to implement multiple model targets

Hi! I'm trying to implement an industrial maintenance application with vuforia model targets within Unity 3d: basically i'd like each model target to get activated once the previous one is detected (my application proceeds by steps). I've trained my models within a single database but i'm not able to tracked the elements. Now, as for trained databases I know that guideviews won't be displayed at runtime in unity, but since i've defined some code logic  on tracked events i'm sure the system isn't recognizing the object. How could i work on that? I tried with a custom script to show guideview for trained models but it didn't work (it was just to be sure the system was actually tracking), what could i look for?

thanks, riccardo