Make a form field mandatory based on response in another form field

Make a form field mandatory based on response in another form field

For reference, see my Creator form at  http://www.jaxareagolf.org/index.php/meeting-notice%E2%80%8E.

In the Attendance Options, if a user chooses "Meeting, lunch, and golf",  I want it to be mandatory that the user also put a response in 'Tee choice:' and 'Handicap INDEX'.  I am not quite sure how to go about doing that.

I would appreciate any help.

Barney