Map to a specific device inside an Instrument Rack?

Is there a way to map a controller to a specific device that is grouped inside an Instrument Rack?

I would like to control the macros of the first device inside my instrument rack. If I set up a Device Parameters mapping with Track Type = Selected and Device Chain Number = 1, then it controls the macros of the instrument rack itself, not of the first device inside the rack. If I set it to Device Chain Number = 2, then it controls the macros of the next device (if any) outside of the instrument rack.