Given the scenario you laid out food supplies will evaporate in days unless somehow a large stock is in storage. 100 people will need over 40,000 lbs of food for just one year.
I would have a similar issue but figure isolating only about 14 homes but a smaller area. That would be close to 50 people if they stayed or were home at the time of the event. I’ve come to the conclusion that closing the road may attract more attention from thousands of near by residents. I might be better off letting them pass down the road. Otherwise it would take serious dangerous methods to keep them away.