Create and initial sigon program for that user and change their USRPRF to use it.
In that program use the TFRJOB command. YOu can put in a JOBQ that is associated with a different subsystem.
If you name the devices in a similar fashion (eg. other*) you can add a generic Work Station Entry to assign these devices to that subsystem.
ADDWSE SBSD(OTHERSBS) WRKSTN(OTHER*)
Now all devices starting with OTHER would start under the OTHERSBS subsystem.