[UK-CONTEST] External control of main & sub VFO on FT1000MP

[G4FNL]

I wonder whether anyone assist me in pointing me in the right direction to
enable me to externally control the Main and Sub VFOs on the FT1000MP?

The scenario is that when operating with the "big knob, little knob" set-up,
it's difficult for two operators to access the smallish push buttons on the
front of the radio. It's even more difficult to see the associated LEDs that
identify who has control. I would like to control these VFO buttons from an
external switch box - but not sure how to do it. Any ideas?

Graham G4FNL