greenlight is passing some metadata on a create api call, and using callbacks to maintain the state in table in postgres.
you can create a meeting in greenlight and look at the actual create calls made with the api in nginx logs, and greenlight logs. Once you understand this may be able to mimic greenlight to have your app create/join meetings
Its possible to link your apis to work with greenlight meetings, but you need to understand how greenlight names the meeting and passes these to create call.
regards,
Stephen