Controlling size of ifs objects

Project:  Set up ftp site for a particular division.  This division must 
have the ability to add users on their own.  Users must be restricted to 
their own directories.  Directories should be restricted in size.

I thought of an IFS structure like this:

ThisDivision
  GodlikeCustomer
    Upload
    Download
  OtherCustomers
    Upload
    Download

The easy parts are:
- storing the dummy users in either a file or a validation list
- using an exit point program to control which user id can do what action 
upon which directory.

The part I am struggling with is controlling the size of the directories. 
Traditionally you would assign a maximum size to a user profile.  Granted 
I could do this.  And the exit point program could say dummy user XYZ is 
really iSeries user ABC.  So, either I create one user profile for all of 
this and if one customer fills it up, then all are locked out.  Or I 
create a separate userid for each customer.  The division administrator 
would need access to all of the directories.

Any thoughts?

Rob Berendt
-- 
"They that can give up essential liberty to obtain a little temporary 
safety deserve neither liberty nor safety." 
Benjamin Franklin