Remove transparent pixels from transparent png

Hi I am creating a map in flash cs4 with all the countries on it. I used photoshop for creating the map and separated countries. Now I imported all pngs in Flash and I want to give Mouse CLICK event and Mouse Hover on all pngs, but as the transparent pixels are overlapping the other states, it is getting difficult. So, I converted all pngs in movieclips and now then I broke up pngs. Now I want to delete all pixels having alpha 0 using eraser tool, as per the borders. And I have to do it manually for individual countries. So is there a way to remove transparent pixels from the bitmap data? Please let me know. Thanks.