I'm posting from my phone, so I can't go into as much detail as I'd like.

Code:
var tipByTxt:Dictionary = new Dictionary();
tipByTxt[txtpName] = "some text";

txtpName.addEventListener(MouseEvent.MouseOver, showTip);

function showTip(evt:MouseEvent):void{
  var tiptxt:String = tipByTxt[event.currentTarget];
// do stuff
}
For each new thing with a tip, you define an entry in the dictionary and add showTip as a listener.