Also found the:
Jtek ShiftMate Bicycle Shifting Adaptor
https://www.sheldonbrown.com/harris/shiftmate.html
Jtek Shiftmate
https://www.peterwhitecycles.com/Shiftmate.php
Which is supposed to allow different SIS shifters to work with different cassettes.
Including Shimano with Campagnolo, or vice versa
Company website here:
Shiftmate 2 for mating different speed shifters to different speed drivetrains.
This model is for mating different speed shifters to different speed drivetrains.