Dual boot w/ FDE

I'd like to have a notebook with one physical hard drive that has two different operating systems (each on separate partitions). One less sensitive OS for general personal use, and another which will have more sensitive work-related information.

I'm trying to find a way for each OS to have it's own FDE w/ pre-boot authentication. Currently, I can accomplish FDE w/ pre-boot authentication by loading a dual OS environment and then adding the FDE after both OS's are loaded, but the drawback is that they then SHARE the same FDE, and the user simply selects which OS to boot using Windows bootloader.

I think the more sensitive OS and its files could be hidden from the less sensitive OS by using BitLocker, but again... nothing prevents someone from simply selecting the more sensitive OS using bootloader.

My ideal situation would be a 2 partition system (one for each OS). The less sensitive personal OS w/ FDE would automatically load when the machine was powered on. To get to the more sensitive work OS, you'd have to have a USB flash drive (or CD/DVD) which would carry the FDE pre-boot authentication and tell the machine to boot from the OTHER partition. That way, the more sensitive partition simply looks like an empty partition unless you know better.

Any thoughts? Other scenarios?

Thanks,

BigSlick