Changing auto-generated pagination links?

[eluser]pluus[/eluser]
Hi, I'm struggling to figure out how to change the url format of pagination links.
Let's say my bbs page generates an url of 'board/20' for the next 20 results...
but I'd like the url to be 'board/[another number comes here]/20' to pass addition info
to the next page.

Is it possible? using 'base_url' maybe?