Mass emailing with outlook?


My mom is a teacher, and today she asked me if there’s any way she could email all of her students parents without having to manually write in all of their email adresses. I said I would look into it, but google has only given me either complicated programs, or expensive ones. Are there any free ones? Or better, can you do this directly in outlook? My first thought was that she would set all the parents in the same company, and after that just write in the company name as the reciever. That works in Firstclass, but I’m not sure about outlook.