I think he is asking for the ability to perhaps send a mass email to everyone registered (or just specific groups) when a new event is created?
That would be kinda cool
Not sure how you would impliment it though, without everything getting very messy (for larger boards).
As I see it, you would need to have an option to either send a PM or email, then a scroll box with all of the groups listed, where you can CRTL+Click all the groups you want to inform?
Maybe have an admin backend feature where you can setup some rules?
Maybe have a similar setup as above, but then have the ability to save your selection as a rule - maybe called "GA Ladder Members"
So whenever there is a GA war, you choose your GA Ladder Members from a dropdown box, and click 'inform'?