Mapping B-3 drawbars with 2 KeyLabs

I’m trying to set up a Hammond-style dual-manual rig with two KeyLab Essential 61 MK3 controllers and the B-3 V2 software instrument. I’ve got the upper and lower keybeds mapped to the upper and lower keys on the virtual B-3, but I’m having trouble mapping the drawbars. When I remap the upper controller’s faders to the upper drawbars, it also remaps the lower faders to the upper drawbars, and vice versa. Is there a way to make this work?

Are both Keylabs sending the data for their faders using the same MIDI CC#?