Hi Chris,

Paul Gaboury showed once in a video, how to poly group a CAD model fast.

https://www.youtube.com/watch?time_continue=1&v=IzFZfJDQOOM

starts at 39:04.

Then you have also the option with MoI to create with a script random
style colors to a model and can use these for poly groups in ZBrush.

But to be honest why to auto-retopo a *MoI* CAD mesh... MoI has the
best mesher available! :-)

Regards
Stefan