Thanks to a quick Google Search, a solution was found:
Tip: To exclude a user from a hashtag search, add a "-" in front of their username. Eg. "#AIPAC2010 -DC_Convention" #AIPAC2010
— Yoav Lurie (@yoavlurie) March 21, 2010
Turns out, this totally works. So I reconfigured the twitter feeds for all incidences of the search query.
Now, if you search Twitter for #nhv, you will be informed largely about the best up and coming band from Indonesia. Here on this site, however, we're safe from those entries. Meanwhile I've been petitioning them to try a different hash tag more directed at the Nashville music scene. -Ian O#