<p>i think you get to choose which colleges you want to submit before you submit...it's just that when you hit "submit" for that college...the version you submitted becomes locked...so if you want to change it for the other colleges that were on that version you must move them to alternate versions.</p>
<p>There's no way to submit the Common App to all your college choices at once... you have to submit it to one college at a time. Which sounds like exactly what you want to do (submit only one app now, and the other ones later), so you're golden.</p>