Reorganizing Battery Priority

I am a big fan of battery life, and have a IBM T60 that gets rather excellent battery life through its built-in battery. However, since I am such a BIG fan of never having to plug my laptop in, I've gone one step further and I own, as well as a backup main battery, drivebay batteries as well.

The problem I'm having is that Windows labels the drive-bay battery as a secondary battery, and it gets drained first. As a result, the batteries capacity gets absolutely raped and after 6 months it can hold less than half of its design full charge.

So is there any way to reorganize the battery priority in windows, to make it drain the primary battery BEFORE the secondary battery, or else to change the labeling of the batteries themselves?

any help would be greatly appreciated