[physfs] Filtering which directories are allowed

[Sik the hedgehog]

Silly question, is there any way to filter which directories can be
loaded when mounting an archive? For example, I want to allow mods in
my game by letting users put files in a 7z archive, but I want to make
sure only files within specific folders inside the archive can get
mounted (for the sake of extra sandboxing). With directories I can
just generate the directory names I want and mount them separately,
with archives as far as I know I can't do something like that.

If not possible, would it be possible to add functionality for
something like this to PhysicsFS?

PS: as you can imagine all those archives would get mounted at the
root of the virtual filesystem, so filtering which directories are
mountable is also an acceptable solution for me.