I don't think this would work for me. I will have 4 arduinos. I need them to start a given behavior (let's say : execute a function) at the same time. For example, in the loop function I'll tell each of them to run the function MyFunction() when time = 2 s.
The problem is that each arduino has its own clock so I can't make them start in the same instant. time = 2s for the first arduino is different from time = 2s for the others etc.
Any time lag would cause trouble even few nanoseconds.