External event class


I am see all the time that well written actionscript has external event classes. If I have a few movieclips how can I write an external events class for them which controls the events.

The situation is that the movieclips need to have different classes controlling how they look, where they are positioned etc. But I would like to make an event class because they all have the same events attached to them. Also how do I attach this events class to the buttons