How to pause replication until a web request is cached?

I’m trying to cache stuff from a database on begin play on both server and client (in BPs but can move to code if needed). I need replication to the clients to wait until the client has their cache updated. Is this possible?

Im not talking about just RPCs, its also NetLoad logic and all other forms of replication. Like OnRepNotify stuff. Im asking if theres a way to start/stop replication to a client.