@evantill, the #groupname syntax where you write a private message and then add #groupname to the recipients does not work in my setup. I tested several combinations (@#groupname, #groupname, from an admin, from a group member).
The nearest think to the mass email sent to all parents in the class is to publish a Topic or Message containing @ notifications for all the parents in the class. There is a defalt 10 notification limit that you can configure in www.example.com/admin/site_settings/category/posting
max mentions per post
Maximum number of @name notifications anyone can use in a post.
However, a large notifications limit may lead to abuse, and it is cumbersome to write such a mass-CC Topic. In a class with 27 children you may easily end up with 40+ parents (both fathers and mothers).