Yamaha DTXpress/DTXplorer/DTXtreme

I have a rather large DTXpress 2.0 set.

Here's the scoop...

5 single pads (65s) (HH, 3 mounted toms, 1 tom next to HH)
3 dual trigger pads (80S) (ride, 2 floor toms)
1 3 trigger pad - snare

1 single trigger cymbal
2 dual trigger cymbals

2 BPS80s (splashes, cowbells toerh fun stuf!!)

1 kick & high hat pedal.

Okay...so I got all that out of the way. My deal is I only have one 
module (DTX 2.0) I need another. One will control cymbals & BP80 and 
the other will control drums.

I need suggestions. I'm leaning towards another identical module. 
Simple to learn obviously. But have a few questions

1. How will I be able to hear both modules through headphones? Is 
there a device that combines both outputs to a single?

2. If I get a different module with different sounds can the two 
modules "share" sounds via MIDI? (I am MIDI ignorant...very!)


What would YOU do?

Many thanks! This is my first electronic set. I waited many years to 
be able to afford this many drums! I'd like to be able to use all of 
them.

Ken in Kailua-Kona