Phoenix presence & presence_diff messages

Intercepting would be something like this?

intercept ["presence_diff"]

def handle_out("presence_diff", msg, socket) do
    {:noreply, socket}
end

The target is to use the channel for sending in-game data and event to clients and utilize the presence internally on the server-side. Client side would only connect the websocket (swift / iOS, Android) and get updates on the game events.
Clients wouldn’t get updates on who is online and who is not (prevent players for example attacking players who go offline in the hopes of catching them off-guard)