InfoPath Dev

I should mention that I'm aware I can concatenate 5 AND conditions in a control's data validation options but unfortunately I have more than 5 checkboxes.

Hi How do I validate a group of checkboxes on submission to ensure that at least one checkbox has been selected? (InfoPath 2007) I am deploying this form to the browser in Moss rather then the infopath client. Not sure if that matters. Cheers