Understanding User and Group Quota system to limit web hosting storage

So I’ve been looking at the DigitalOcean guide for setting up the Quota system, so you may limit how much space a user can take up. This is usually done on /home, however I’m about to set it up on the /www section for all the webhosting. To clarify, each domain is hosted with an SFTP only NO SSH user, so the /home restriction isn’t necessary. The www area is also set as the root for this group of users.

What I want to know is: If you apply a Group Quota to a folder/volume, does that mean the combined group’s amount of storage is limited, OR, each user within that group has this limit?

I ideally would like to set a policy that each user has the same X amount of limit in this web host area, without needing to edit existing users / manage new users better. Can I define a group policy of 100mb to the web folder, thereby limiting each user to a 100mb area? Or is there another way to do this?

All else fails my new user bash script will have to include manual limitations per user. For large scale though, is there a way to globally apply this?