I found this in the provided condor_config:
## If you want condor_submit to automatically append expressions to
## the job ClassAds it creates, you can uncomment and define the
## SUBMIT_EXPRS setting. It works just like the STARTD_EXPRS
## described above with respect to ClassAd vs. config file syntax,
## strings, etc. One common use would be to have the full hostname
## of the machine where a job was submitted placed in the job
## ClassAd. You would do this by uncommenting the following lines:
MACHINE = "$(FULL_HOSTNAME)"
SUBMIT_EXPRS = MACHINE
Ralph Finch
Calif. DWR