Adding multiple kits to the drum rack.

[andrew.scandal]

I'd like to add multiple kits to the drum rack. Clearly, with so many octaves available in the drum rack view, there is room for many sounds. But when I drag a second kit onto the rack in a different portion of the rack, it still replaces the first rack.
Also, is there any way to consolidate them? I'd rather that they be consolidated so that each key has a drum sound. I don't quite understand why some keys have a drum sound and some don't.
Thanks!