Well here you go.
I'm making a singleplayer map and I'm considering to put this feature in it. PB2's inconsistent copy-pasting is a pain in the ass tho. Let me know what you think.
Map ID: crestfall69-breakabletest
EDIT: It's been around a year and I returned. I updated a few things in the map. I feel like there is a much easier way than making individual triggers for each wall. If anybody got an idea, holler me.