Creating url path from token with more than one word does not hyphenate..

I'm trying to create a menu with the url links created using tokens. If the token has more than one word (ie a group called Factual books), the url becomes -

mysite.com/groups/Factual books

what I want is -

mysite.com/groups/factual-books

as this is how the rest of the paths on my site are set up (thanks to pathauto), so the first example here is just a broken link..

Is there a way to ensure the path is set to hyphenate like this (and all lower case)?