Yamaha DTXpress/DTXplorer/DTXtreme

Ok, so I've got 3 brains...well half a brain actually :/ .. but I do 
have 3 drum modules...I've only got 2 hooked up for now. both my 
DTXpress I and DTXpress III modules stereo outputs are connected to 
my small mixer which then can go into my sound card.
I know I can go straight into my Aardvark Q10 audio card with it's 8 
inputs, but I was wondering about any way to 'link' the modules 
together so that one of the modules had all audio output from 
both...? I 'thought' I read this before...Maybe I just pulled this 
idea right out of my dark spot!...?
If not I suppose I can just keep using my mixer for multiple outputs 
from my two modules and soon to be three modules.

Steve