How to authenticate / authorize for a single Google domain?

[jcdarwin]

Not being any sort of expert on oAuth, I can see that I can use this project to authenticate against Google's oAuth service for my various Google accounts.

However, if there's only one Google domain that I want to support login for (e.g. a G Suite domain for a business), but not the others, how would I go about configuring this?

I'd guess I'd use the Custom Google provider, but I couldn't find any mechanism for doing this.

Any pointers here would be much appreciated.