Good morning, Hoffy;
While I cannot specifically state that it will work in the way that you are describing for use with your Bronica, there is a Metz SCA adapter here for use with my Minolta cameras that does require 4xAAA batteries in it to work, and it does measure from the camera location the light intensity of the area being illuminated by my electronic flash units. There is even a selector on the back of this SCA adapter to adjust its sensitivity up or down a couple of f stops. It is for use with AF cameras also, so it should indeed be capable of working in a manner similar to what you are describing.
Where did I put the instruction sheets that came with those? I know that I have the regular manual for the 60 CT1. These oblivious questions are so hard to answer.