If you need them destroyed forever, even after loading a save game, or changing layouts to another and back, you could use a hash table, and add/store keys like..
On start of layout:
Set global 'number' to 0
For each family_destroyable
- number: Add 1
- Set family_destroyable object's variable 'id' to number
- Hashtable: If key: LayoutName & number Doesn't exist, then add it
- Otherwise, if hashtable key LayoutName & number Does exist, and it's 1, destroy this family_destroyable object.
Then when destroying such a thing:
Hashtable: Set key LayoutName & family_destroyable.value('number') to 1
So you'd end up with a hashtable key names like, for a layout named 'Some House': Some House0, Some House1, etc.
I suppose they'd get out of order when deleting one of the destroyable blocks.. Still, it's one way to do it.
In short, using a hashtable to keep track of which objects are destroyed. You can then save and load the hashtable when needed.