How to control A4 frequency on polyphonic synthesizer?

I have a very small project, which is to create an interface for controlling the A4 frequency on a very simple polyphonic synthesizer, but when I try to change the A4 frequency, it only affects the first voice in a chord, and I don't know how to send the message with the new A4 frequency to the other voices within the same chord.

Any help would be appreciated.

Attached are the project files for my first version of the a4 controller on a monophonic synth, and a polyphonic synthesizer with support for 16 voices I downloaded from the internet.