Events don't really go sideways in ActionScript by default. They bubble upward. If you want to send an event sideways, you will probably have to coordinate with something higher up in the event hierarchy. You can send the event to a common ancestor, and then pass it down the hierarchy as a method argument.
Another option is to use a framework that supports Injection. There are a number around these days. The one I'm most familiar with is Mate, which allows you to handle events and inject data in MXML. Mate is meant to be used as an MVC framework, and you may want to look into it if your application is complex, but you can also use it to coordinate global event handling if you don't need that level of structure.
This gets discussed often on the forums. Try searching for prior threads