Multiple instances of Session Drummer 2 (SD2)

So here's what I want: I want to have two (or more) instances of Session Drummer 2 in a project. For each instance of SD2, I want a number of tracks for each pad (i.e., one for kick, one for snare, etc.). However, when I attempt to set this up, as soon as I add a second instance of SD2 ("Insert Synth"), I get all sorts of pops and clips. For example's sake, let's say I have to instances of SD2: X & Y. I have four tracks (kick, and snare for each X, & Y: I set a "1" below the kicks, and a "2" below the snares in the SD2 interface). Now, I open X's SD2 interface and click on the kick, triggering it. When I trigger it, X's kick track and both Y's tracks (kick and snare) all show clipping. What in the world am I doing wrong???