I can't think of an easier way than to create a little batch file, making a shortcut for it, and running it when needed [possibly with a hotkey]. The batch file would be something like:
cd "program files\where your files are"
attrib *.pmn +h
[and make the shortcut 'close on exit']
note: - When folders have more then 8 characters such as in the example above, use quotes, otherwise they are not needed for 8 characters or less.
There may be another way of doing what you want. This is the only way I can think of right now.