The Group Account feature is available to all DriveHQ services (incl. FTP, Cloud File Server, File Sharing, Email Hosting, Backup, etc.).
First of all, make sure you have a group account. From the DriveHQ.com website, hover your mouse on top of DriveHQ logo to display the DriveHQ Start Menu, click Group Account or Group Admin. If your account is a standalone account, you need to upgrade it to a Group Account first. You can then use the Group Admin feature to create sub-users. DriveHQ offers one free sub-user license. If you need more, our user license only costs $6/user/year.