I think it would be great to be able to invite or select to send out a notification for and article to a group or groups that have access to that section. There is an option to send an invite to an individual and an option to include a group/s. But you have to include an email.
Maybe instead of reworking the current Invite option there should be a new one that allows you to send out a notification to all the users in a specific group adding in the option along side the Invite, Star, Share, and Flag which is found at the bottom of a completed article/post.
I use this for internal documentation at my work place where everyone is segregated in to their own little groups and categories and I find that this would be a very useful tool to have.