How can I MIDI control 1 octave lower to my current note?

I’m trying to layer two synths by playing them hooked up on MIDI, but I want to play let’s say Synth A on the upper keys and Synth B do the same notes on a lower keys… whenever I go and hook em up both synths play the same note

I can’t send message to it from the Octatrack as it still does the same

My goal is to layer the synths so I can record them quadraphonic on the Octa in a single go instead of using 2 tracks and re sampling them together

(Korg Opsix and Modwave if that matters)