Using School Buddy for Schools, you're able to send a message to your entire contact list within seconds. The amount of contacts you're able to have is based on your plan, but this can be changed at any given time from the admin panel.
Each contact on School Buddy for Schools is allowed to have the following information attached to it:
Two Phone Numbers
Two Email Addresses
At the moment it is only possible to send a phone call to a contact, but email support is on the roadmap.