Whitelist accounts when using Gitlab SSO


I set up GitLab SSO on my self hosted mattermost running in docker.
I have it working, but I am wondering how to choose who gets to access the server.
There is no inviting to the server, and it seems that anyone with a GitLab account can log on and create a team. I only intended for it to be used by a small hobby project group. Is there any way I to whitelist gitlab accounts?

This setting might help: https://docs.mattermost.com/administration/config-settings.html#restrict-account-creation-to-specified-email-domains.