|All files with the same extension will have the same icon, normally dictated by the program writer. If you somhow manage to change the icon for a particular file type then they will all change. Instances like zip, rar, jar and xpi are again dictated by the program writer. There is no way around this to my knowledge.|
Shortcuts to any given file extension can all have have different icons, either using the selection Windows gives or .ico or .icl icon files that you could collect from the internet and store in a folder somewhere.
Always pop back and let us know the outcome - thanks