xdj-aero - routing line inputs to rekordbox

I have an XDJ-Aero.

I'd like to route the audio (via USB) from the XDJ-Aero's Line 1 & 2 to RekordBox 5 running on my Mac. 

The goal is to hear these channels in the mix via the Mac's audio out, with the intention of eventually streaming the mix online, in real time.

Even if I can only listen to two channels at a time, that's fine; I could switch between the deck/line inputs on each channel as needed.

Forum searches here reveal that some rekordBox compatible devices route the Line inputs via USB. I found nothing relevant to the Aero however; only a few discussions surrounding DVS, which I'm not trying to use in this case.

The manual for rekordBox 5 doesn't mention the line inputs, so I'm at a loss.

Thanks all for any assistance.

The only other option I can think of to get the complete mix is taking it out of the booth/record jacks of the Aero, and back into the Mac via a USB audio interface. (My understanding is the MBP's mic jack is mono, so that's a no go.)

I'm using a 2013 MBP 13" running macOS Mojave.