There have been some conversations around adding an occurrence counter to alerts. This would increment an existing alert if another violation happens while the previous alert is still open. Mostly around event sources; if you get 12 traps about the same thing, open one alert with a count of 12 instead of 12 alerts.
The same thing could be extended to this, but something would have to define whether the existing closed alert would be reopened/incremented or a new alert opened. Probably could be as easy as "for this instance, within X minutes of opening/closing, increment instead of opening a new alert".