Ka-50 Radio Select Rotary -- Lua vs. DCS-BIOS

[Alterscape]

I'd like to connect a rotary switch to DCS to directly set the active radio on the Ka-50 (the rotary on the left knee radio panel). Is it possible to edit default.lua to bind specific radios, rather than just "increment left" and "decrement?" I'm pretty sure DCS BIOS can do it, and I'll probably go there eventually, but I'm trying to set up something quick and dirty for now.