this is possible, and i’ve done it before, but i don’t have an example offhand of how to do this as this particular code is part of a larger project I’m working on. If I get time maybe I can separate it from the larger whole. it’s also unfortunately a little more complicated as you would have to change the plugin to support multiple servers.
To support multiple servers: you would write an obj-c method that initializes the server, taking in a string name in Start(). that method would return the instance as a void pointer, (IntPtr in C#), back to unity, so that you could keep track of your multiple instances as IntPtr references.
Once you have multiple syphon servers created, you just need to send your NativeTextureIDs + the IntPtrs (server instances) back to the plugin to publish the servers.