Notification from comments on activity stream underneath custom events

Hi Kyle,
I have set up an auto action to always show a stream underneath an event in a third party component. These activities have the asset "event.[ID of Event]"

Now, I would like to send a notification to the event creator and everyone who is registered to the event when somebody creates a new activity on the event.

I would need this notification to have a special asset (eg activity.event.[userID].[ID of Event])

How do I go about this in the best way?

Review "CB Groupjive - Stream Notification" system action in CB Auto Actions > System Actions for an example of logging a notification from a specific stream based off asset with custom set of recipient users. You'd need to write your own User code, but should be a solid example to get you started.