Nayan,

If you want to see all users in your own organisation and below, that is possible now using content restrictions (the content tab when editing a report). Currently you can only do it in certain reports like the course completion report but we have a patch to add that to the user source which will be in the next release.

If you want to see all users below you in the management hierarchy, that is not currently possible, although we do intend to add it at some point.

Simon