For my setup downstairs, I have an Epson Powerlite S5 projector, a MacBook, and a 19 inch(?) Apple Studio Display. What I wanted to do was to run the signal out through VGA from the MacBook to the projector, and then run the Apple Studio Display out through the projector's Monitor Out port and into the output on the DVI to ADC adaptor from Apple that is needed for that monitor. That was done using a 12 ft. VGA to DVI cable I had bought from Amazon. When I hook it all up, the signal goes from the MacBook to the projector but not back to the Apple Studio Display. If I replace the Apple Studio Display with a different monitor with it's own VGA cable it works fine. Is it the cable that is causing me problems or is it something else?
A diagram can be found below:
Please help!!
A diagram can be found below:

Please help!!