Can I apply File Server Resource Manager (FSRM) quotas on a per-user basis?

A. No, unlike the built-in per-user quotas in Windows Server 2003 and Windows 2000 Server, the FSRM quotas are based on the folder or volume, and the quota applies to any user that writes to the folder. If you want to restrict who can write to volumes or folders, use standard NTFS permissions to restrict the users who have write permissions.

For example, if I want to limit a folder called "Sales" to 500MB and allow only members of the sales group to write to the folder, I would apply a 500MB quota and use NTFS permissions to ensure that only members of the sales group have write access.