C3D uses a “Probe Adapter PCB” for a Probe+BitSetter combo (pg. 7). As there is no electrical components that I can see on the board, I imagine it is just wiring the two Normally Open (NO) probes in series, vs if they were Normally Closed (NC) in parallel, I’ve seen this type of wiring for example via multiple hard limit switches.
While I personally like to run my probes and switches NC, you can switch the Probe I linked on the other thread to operate in NO mode to simplify wiring (after had suggested their converter at first).