as @keymanpal really theres quite a few different ways to do it, depending on available cables/hardware 
but lets keep it real simple… and just extend what you have
so you currently have
Logic → MOTU → din-usb ->Organelle
make this bidirectional… by plugging in the other din… this is generally a useful setup , so you can record organelle midi
Logic ↔ MOTU ↔ din-usb <->Organelle
then buy another din-usb cable, then again, create a bidirectional connection (by plugin both din in/out in)
Organelle ↔ din-usb ↔ Juno
(you will need probably need a small usb hub, as you now need to usb ports on the Organelle)
so Organelle usbhub → din-usb x 2
then watch my video on ‘advance’ midi configuration…
you’ll need to watch it all to understand whats going on, but near the end I explain how I set up a ‘midi thru’, which is basically what you want…
you want to connect , you want:
Juno <->din-usb ↔ Organelle <->din-usb<->logic
note: if you din-usb cable acts like mine (ive a midimate) , you’ll have to be careful which ‘ports’ to use for in and out
e.g. in 28:1 … you might find it needs to be :0 for one, and :1 for the other… depending on which din you have plugged into in and out
if you set up the routing correctly, actually this is not a requirement, as the routing is all done at a device level.
(though you will need to be careful you setup Logic not to echo its input to its output)
however, you might find it easier to use different channels initially, just to for it to clearer in your own mind.
you set set the input and output channels of the Organelle in midi setup… note: this is only for ‘defalult midi’ generated by mother.pd
this is the simple/cheap case, there are many other options, e.g. using midi routers, this might be a bit more efficient too, but probably a bit more expensive… and then you have to think about the setup.
