What about running the job in a named job queue with a limit of 1.
Jobq= on !JOB command. Set limit of 1 on queue .

Sorry I do not have access to an HP3K anymore to get the command
specifics since my layoff, but I used to use jobqs to limit the number of
jobs of a specific type to a certain number for performance and file
access reasons.

(still following the 3K newslists)

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