Make neutral building hidden in fog of war

[Shrrignien]

Hi,

Is it possible to make neutral building invisible/hidden in fog of war ?

Because i'm using some villagers as building, but when they are out of sight, something strange happen (picture uploaded) : their location seems to be updated (yes they can walk) but their prevous location isn't delete, so they stack has hell...

I know I could set the "is a buidling" to false, but I really need to keep them as building.

I'm looking for something like :

hide unit in fog of war : true

But I don't know if there is such a thing...