MediaTailor Ad Insertion Automation - Any Ideas?

I've had good success with MediaTailor in terms of adding pre-roll ads and mid-roll ads during Program specification. The issue now is automation: while I can manually add ad breaks as part of the program information, this is a cumbersome process for long-form VOD (specifically movies). Does anyone know how to automatically create ad breaks - on par with "put an ad break every 5 minutes in this two hour movie" without having to individually specify each break in milliseconds?