I'm probably oversimplifying things in my mind, but should a range based culling of objects not be pretty much straight forward? Calculating the distance between objects and the clients, and drop everything that's, for example, more than 50km away, as first and basic implementation? And/or maybe include a flag for the client, to drop the object from the update calculation for now? I mean, you have all the info, and calculating the distance between two points is, as far as I remember, pretty simple vector math. Is it that the Engine only allows one single update set for all clients? Or is there no good central point to implement this? Or are you trying something much more complex, but if so, why not start with a simple 80% solution? I really would appreciate if someone could give me a better understanding about what the technical difficulties are exactly.