I got an app which segments the users into different communities, similar to clans or guilds in other games.

The users choose which community they want to join as a part of the sign-up process, and can then interact with said community within the app.

I would like to have the option to send out push messages only to certain communities, and were wondering how I create a custom audience in Firebase based on which community they're in? Ideally, I would like to create one audience for one community, and then just be able to select these different communities when creating a notification.