That are good news. I am happy that everything is working like expected. To let you know: we are planning to introduce an improved notification API for the ESH framework as well as a way to group different audio sinks to play audio synchronized.
Why do you think that? To use such a proxy item is a basic design pattern for smart rules. I have created nearly the same amount of unbound items like items linked to a channel. Just for more flexibility and a better way to control the behavior of my own system.