RSS question

situation: My site serves a neighborhood in San Francisco, CA. We have earthquakes in Northern California. About once a month we have a 5.0 or greater. 2.5s happen weekly in N. California. These are tracked and reported by a government group that is also (on the same feed) reporting Oklahoma, Iran, Australia and any other 2.5s anywhere in the world. (I do care about other places, but relevance to the neighborhood is lost when 1 in 500 relate).

question: How do I restrict my RSS pull to just California? There was a feed for 2.5 in Northern California but that was removed. California is in the title, when the quake is here.

This is more an RSS question than xenforo.

Thanks in advance Ed