Icon per application instance

I use multiples of the same program (Dev Studio, Excel, Word) and I want to know which one I am working with and they all load with the same name/icon.  I can change the icon on the Tiles page but when I move from page to page the last icon replaces all the icons when I go back to my list apps running.  It would be nice if an icon can be assigned per running application document or just keep the icon assigned between page swaps.