Spindoctor there are a number of way to do this.
You can do layers, and since that's been explained somewhat, I woun't go into detail on that. Splitting the children on your layer channel will send each sound to a different key on that layer giving you what you want.
You can use the FL drum synth. Hope you bought it
You can also use the FL slicer- If you wanna use the slicer this is what I would do.
open up all of the drum sounds I want channels. sequence the sounds about one step apart or more til each sound is islolated to your desire. Then export it as a wav. Open a new FL session, open that wav in FL slicer, and slice it, when you slice it, each slice will be controled by a different key.
There are more complicated ways to do it which will allow you more control, but the more complicated the technique, the more words I have to use and I gotta run. This should be good enought to start wit though. Later