how to build two while loop in one while loop with different starts and stops

hello guys;

i have project to do 8 power supplies in one program, so i did every things about this project but i need starts and stopes for each and one start and stop for all power supplies.

for example:

i need each power supplies 8 V output then i need to stop first one then start without use run button.
if i need to stop and rest all power supplies to press one button..

best regards