I am not going to hitch a ride with either train here, but a business is a business. It would be nice to be sent a letter informing them that they were not a fit for this position but you will forward positions in the future that may be of interest to them. If Sean is a highly qualified teacher than you would do best to let him know and keep on good terms with him for future vacancies. Let's be frank. Businesses don't care about people's feelings unless it suits their interest. I think it could suit your interest in the area I mentioned.

I could understand that it would be difficult to contact each candidate. Might be a good idea to setup a mailing system for that.