Ability to hide only "To" value in date

Hi,

I would like to use this module with the Date module to toggle between asking for a single date and a date range. Right now, you can either show or hide the entire Date field; I would like to be able to show or hide only the "To" part, not the "From" part. I'm not sure how hard this is and if it would be better broken out into its own module...

Thanks.