Pretty Links Without Page Hierarchy

I’d like my pretty-links for pages appear without the hierarchy of pages in the URI. I’d prefer that just the target page name appear, possibly prefixed with just the word ‘pages’, like this:

http://mysite.com/pages/hello

…where page “hello” is perhaps two levels deep in the page hierarchy.

Can this be done?

I still want my post pretty-links to be unaffected, and appear as year/month/post.