Notify admin upon user joining a specific usergroup

[coRtALoS]

Is there a hack like this?

Currently I am using the inferno warning system, but do not want users automatically banned *trust issue, sadly*. Still though, I want to be notified when a user hits 10 warnings. What I was thinking, is making a new usergroup, like *awaiting ban*, and have them placed into that usergroup once they hit the warning limit. However, once they get placed into that usergroup, I want to have it so that it sends out a PM, or an EMAIL to an admin stating that *username* has been added to this usergroup. Then we know they have reached their limit.

Is there a hack like this, that will notify an admin when someone joins a specific usergroup?

Thanks!