Simplest thing is to use Phoenix PubSub. Broadcast an "anomaly at x,y,z coordinates" message. Then each process can calculate whether it is close and needs to d

Simplest thing is to use Phoenix PubSub. Broadcast an "anomaly at x,y,z coordinates" message. Then each process can calculate whether it is close and needs to do anything. This isn't very efficient because every process will do some work for every anomaly, but unless your system is very large that's probably OK (it as least extremely parallelised). The alternate approach is to create some form of central process registry that has all the coordinates and process ids, so that you can look up in one place and then send messages out to the relevant processes. There are some other replies about this sort of approach.