How can I create hotspots on an image in Flex 3 to show tooltips?

I have an image that I am scaling with the width of the browser. I want to be able to show tooltips on certain parts of my image to give visual clues but for sizing purposes, I can't break the image into several smaller images. Is there a way I can create a 'hotspot' of sorts on the image to show a tooltip in the same position on the image, regardless of whether it scales bigger or smaller?