Hm. Not sure I fully understand what you mean. inside your main collection which has your collection proxies, the controller should be the loader. You could name the game object “controller” and then the script “controller”. Something in your levels sends a message to your controller (loader) script.
msg.post("controller:/controller", "show_game") -- This is sent to your loader and your loader reacts to this by loading the scene and unloading the current one