Suggestion: Overwrite default browser "on-the-fly"

Hi,

one of the things that bothers me in portable apps is that I need to check for every app how links are opened in the browser and how I'm able to change that to my portable one.

After I was successfull in changing the target browser in thunderbird I completly failed at the messenger. I've made a lot of research on pidgin (it had the feature in the past, but they removed it), miranda and trillian. But no one is able to select a non default browser. And there are many other apps that aren't able, too. f.e. pdfs or simple word documents with hyperlinks etc.

So I've asked myself:
Isn't it possible to change the PortableAppsSuite so it overwrites the local system call "on-the-fly" as long it runs and after closing it the default setting is restored?

regards,
Marc

P.S. if this is possible it could be an idea for specific file extensions, too. Oh that would be nice. Plugin the usb stick and open documents automatically with my portable apps instead of the local ones