cesisco: Thanks for the link! I saw your example long ago and thought it was cool, but it kept crashing if I move it too fast.
Thanks for the help everyone. After quite some time of researching, this is the version I am going for, as it's easiest for me to understand and implement, without going to UID picking and looping.
Here's the capx
, for those interested. It's not perfect, but it's good enough for me.
If any of the expert has a better and proper way to implement this, please do share.