Hello mcbradfords,
This isn't something that getwatchlist does, mostly because it really isn't something I have found was needed, outside of Splunk's capabilities. My suggestion here would be to create a lookup which points to a local file, and then update the file that the lookup is pointing to. Failing that, you would have to have some kind of http server that is serving up the file, but if you are local system access already, I would go with the lookup route. You may also want to look at the inputcsv command. Hope this helps.
Dave
