Check out the function cron_rdf in lib/Scoop/Cron.pm to see how the rdf file is created.
You would want to use getstories() as the cron_rdf function says it should in its comments (see the Scoop Admin Guide for a description of the getstories function) and tell it to get story summaries with a displaystatus (-dispstatus) of -2.
You can then create a new cron item that runs this box as often as you want it to run. Don't forget to change the filename it tries to write to, or it'll overwrite your regular story RDF file.
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