lunch

Process B and C depend on A. Fine. But what if we need to kill B if C dies, and kill C if B dies ? We must kill all the processes in the group "B&C".

with B
if any node in its group is STOPPED:
    kill every node in the group

That would mean that every nodes in that group must be started at the exact same time, so that their state is never STOPPED when any of them is RUNNING.

Let's think more about this.