Is there a way set an alert for an threshold within the region?
The following are Grande (64bit) storage related job metrics.
The metric JOBGPVTA should give you the alert you desire for grande private.
Variable Resourc1 Description
JOBGASTG jobname Auxiliary storage to back G-PVT
JOBGCSA jobname G-COM storage allocated
JOBGPVTA jobname G-PVT storage allocated
JOBGRSTG jobname Real storage to back G-PVT