The peer id only need to be unique within a cluster (or Messagines instances that uses bridges toward each other).uch better approoich
Do you REALLY want to build a cluster with 500 nodes? It's better then to devide these 500 nodes into 50 clusters with 10 in each. This makes it better when upgrading software etc. (You can update each sub-cluster indivual and keep the uptime of the app). With that solution you only need 10 unique perr id.