Setup a folder "user folders/specialusers" and apply a rule to "specialusers", executing the setupscript, whenever a subfolder is created. Be sure to remove the "recurse to subdirectories" checkmark. Now create the userdirs in "userfolders/specialusers".
Certainly, you could do that on "user folders" as well, but this way, you keep yourself the option to create users, which do not need the setupscript executed.
Norgan