I think MOTU will assign some sort of differentiation to the other outs so you know what is what.If I was a betting man I'd say it will know that you have another box hooked to the card and assign 9-10, 11-12 etc and the same for the next box. My concern here is that RB only has 16 ports available. Open RB with and audio track on it and right click on the track. A menu opens.Near the top is port and you'll see only 16. To this means you won't be able to use the 3rd box.

John
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