Thanks for this documentation!
I have Telegram bot integration with HA already running for a while and it’s a great combination.
I see you are using 3 Telegram bots. It’s also possible to use 1 bot and add that bot to 3 (or more) groups.
Then you can send messages to a group using notify.telegram_group1, notify.telegram_group2 etc.
When using this you have to add the chatid of the group (starting with -) to the allowed_chat_ids of the platform.
Maybe this solution is useful for some people as well.