With families i do it this way, looping trough the picklist:
The instances that overlap and have the lowest healtpoints get set opaque, or can be destroyd. A situation that happens a lot.
Without families and no addon, i have honestly no idea how to do the same. Mayby one day i find a way.
(Rex could have answerd you that he has an exellent addon for that)
The thing is. Families are extremely helpfull with picking problems. I understand completely why they are only available in the payed version. Missing families is missing out a huge amount of possibilitys.
But, almost all beginners have no way to know what they miss. They should make there games according what is possible with the free version. But they have not idea how to do that, and they can not have an idea. One of those things is: do not overlap more then two instances of same object hoping their are conditions to snap those individual overlaps. If you do, you work beyond the limitations of the free version.
That is my opinion. (means nothing, everyone has one) And mayby there should be some clear document explaining this, when listing up the differences between payed and free. But on the other hand, in my case, i would not have understood that doc, not even after 20 times reading. I would have come to the forum to read how other people solved this. Luckely this community is heaven.
I cant apologize for my English, i know it is horrible, but i do my best.