This is a case where you typically want to create a custom button component, say myButton. After you create an instance of myButton you pass any info you want it to hold, like the i parameter. When myButton is clicked it emmits a custom Event (create a subclass of flash.event.Event) that holds the i parameter. You listen for you custom event (not click) and once that is fired you pick up the i parameter from your custom Event object, that comes as an argument to your listener function. Or you may want to avoid creating custom Event: listen for Click and pick up the i parameter stored within the myButton instance: event.target.i
I guess there are other ways as well, but I think the ones above are the 'cleaner' design-wise.
