This is not possible currently. buildings can only be enabled for a
player globally, but not forbidden inside an area. This would be
essentially enable - i.e. show it in the menus and statistics - but
can't be build inside an area.
I also have trouble with getting this through to the player. It is hard
to explain that she is allowed to only build inside an area and where
this area ends. I think this would make more trouble than its worth in
this specific case.
This is not possible currently. buildings can only be enabled for a
player globally, but not forbidden inside an area. This would be
essentially enable - i.e. show it in the menus and statistics - but
can't be build inside an area.
I also have trouble with getting this through to the player. It is hard
to explain that she is allowed to only build inside an area and where
this area ends. I think this would make more trouble than its worth in
this specific case.