Can I use the microbrute keyboard via MIDI to play the Beringer neutron?

I have a microbrute and am getting a neutron for Xmas. I would like to play them polyphonically - or whatever the right word is for three separate notes at once. The neutron plays 2 notes at once and will send any extra midi notes it can't "reach" down the line via midi through. Ideally, I'd like to turn "local off" on the microbrute, play its keyboard, have the MB send those midi notes to the neutron (which would play 2 of them), and then send the extra note(s) back to the brute. I do NOT want to use a DAW for this.

Preliminary testing has not been promising. From what I can tell, The brute can only send MIDI out through its USB port, not through the 5 pin MIDI port, which is IN only. That would mean I either need a DAW to take the brutes' USB midi and turn it into 5 pin midi, or else some kind of Arduino converter I make myself, right? Do they sell something like that? All the USB to midi converters out there seem to assume there is a computer invloved. I really want this thing to work with no computer. If I have to build an Arduino project I will. Buy, if I can spend $50 and not learn Arduino I would prefer that ( I have an UNO I've never used)

Anybody got any ideas?

THANKS!