Help me understand "Everyone except external users"

[Deleted]

I need some help explaining how the security group "Everyone except external users" works... We've always assumed that if you're sharing content in a site collection with external users, and the site needs to be open to everyone as a visitor, you need to use the "Everyone" group... because if you use "Everyone except external users" in the Visitors group, external users wouldn't be able to access the site. Is that true? I spent some time searching the internet, but I couldn't find anything that answers that question. I know that external users who are invited to any site in our company can view other sites open to "Everyone" ... I need to communicate to our users that they should be using the "Everyone except external users" group if they don't want external users accessing their site, but I want to make sure that invited external users can still access the sites they were invited to.