Require Alternative URL Field

Hello, Drupal rocks! I had no idea it existed until today and I've already got it setup and I'm loving it. Very user friendly. I'm wondering if it is possible to enforce the 'alternative URL' field under URL path settings when creating content. I don't want users to be able to submit a story without providing an alternative URL. If this isn't easy, perhaps it is easier to put that in a more obvious location?

Any suggestions? Thanks in advance!