Why not create a global chat channel called "lobbyListeners".
Then - when a user is viewing the lobbies - have them connect to and listen to the lobbyListeners channel.
Then you don't need to maintain a global entity at all. Whenever you create a lobby or delete it - send an event to lobbyListeners - and it will automatically send it to everyone who has registered for the channel.
Would that work? (or is there a part of your use case that I am missing?)
Note - brainCloud will now send over the first part of your email address as the suggested username for the forums. The forums will automatically append a number if there are others with that username.
You can update/customize your username by clicking on your profile in the top-right, and choose Edit Profile.
There you will find a bunch of info you can customize about your user account.
Click Change Username on that screen to change your username itself.