Well, you would then have to check for every possible URL if any part of it contains an s at the end of a word and then reroute to the real page, plus change all the site’s URLs to reflect your desired URLs. Guess it would make more sense to either change the URLs manually at page creation or use a panel page update hook that actually changes the UID of the page after the page has been created.
I don’t know, maybe it’s really easy and all you have to do is check with some regex if the URL contains an s followed by a hyphen somewhere and then reroute to a page with a hyphen plus an s plus a hyphen…