2 Subscribing Blogs Under 1 Site

I am wondering if there was a way to have a single site, but have users subscribe for email notifications for just one portion of the site?

For instance: A single school site with a 7 year old class and an 8 year old class. The parents of the 7 year olds can subscribe only to the posts relevant to their child’s class and same for the 8 year olds.

Its ok to have all posts enter into 1 single post page, I am simply talking about notifications being separated based on class.