How to hide objects/ columns when walls go down?

I hate having pillars visible when the walls are down because they obscure vision, and so would like to hide columns when the walls are dropped, mimicking the behaviour of Friezes.

I have successfully been able to change buy mode objects (like mirrors) to drop when walls are down: Object Catalog > PlacementFlagsLow > "ShowObjectIfWallDown".
However, build objects don't seem to have the object catalog?

This must be possible because Friezes drop when the walls do, so I'm sure it must be possible for build items to do this. However, Friezes don't have an Object Catalog so I'm not sure how they're hidden when the walls are down.

I've tried adding the Object Catalog to columns, but I'm not sure how to proceed to get it to work.

And help would be very much appreciated