Hey Emilia!
If you have a Club in Zwift, you can now add a Discord link within that.
It almost sounds like you’re working from the opposite: you have the Discord already and want to start a Club. If that’s the case, here’s more info on creating a Zwift Club: How to Create and Set Up a Zwift Club | Zwift Insider
You can edit the Club settings so members have to be approved, which would let you limit access to the people you’ve verified on Discord.
Further, in the Resource Wiki, we link to popular clubs. I’d be happy to add yours if/when you have links.