By assigning them like rational human beings? It's really weird that you think you can't decide who is responsible for dealing with a type of notification ahea

By assigning them like rational human beings? It's really weird that you think you can't decide who is responsible for dealing with a type of notification ahead of time without "endless politicking and horse-trading", but think that blasting everyone with every notification, then attempting to sort out responsibility after something has gone wrong will somehow not cause "endless politicking". Again, this is something many businesses do already. They don't blast the whole company when a bank account balance is low, when a server's disk is full, etc, notifications are targeted to appropriate groups. The specifics about who gets what is going to vary based on your organization. I can't give you hard and fast rules that will work for every organization, but that doesn't mean it's somehow impossible or not worth doing.