mainly for public viewing you just need the essential authority events to be broadcast along with the rest

broadcast vs narrowcast is critical in any attempt to make nostr usable both as an open public network and as the basis for private/business use and being able to define boundaries... this also definitely requires custom relays as this simplifies the issues of how to make what is intended to be public, public the relay would respond to certain event types by activating some kind of functionality where the relay becomes a client to broadcast to other relays (like a selective version of blastr)