Receiving notifications in a messenger (Riot.im) when a new appointment is set

I´m working in and for a sience group and want to establish some kind of WebHook, so that we get a notification in our Groupchat whenever somebody adds an appointment in the Nextcloud calendar app.
The messenging system we are using is via Riot.im (matrix).
I could not find any helpfull information regarding my problem so far, so I´m really hoping you guys and girls can help me out.

This would require a separate app to listen to calendar changes and trigger webhooks.

you don’t happen to know if such an app already exists and which one would be best suited for it?
Our chat group should support an Rss feed bot.
I´m new to this whole topic so its a bit troubeling for me ^^

There’s no such app right now.
Someone could build something based on https://nextcloud.com/workflow/, you may ask in https://help.nextcloud.com/c/nextcloud-freelancing/48

Okay, thank you very much for your help