Did you try searching for "roller" in the door object settings?
This is what I get in the default AUS library - I assume it is in the other national libraries as well.
It isn't an exteranal shutter as such, but is it any good?
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10