Complex sentence: In 2007, its news department won seven Edward R. Murrow Awards--the most wins by any U.S. station--in the news series, feature, news documentary, spot news, continuing coverage, newscast, and overall excellence categories.
Split into simpler sentences: In 2007, its news department won seven Edward R. Murrow Awards, which is the most wins by a station in the country. The station won awards in the news series, feature, news documentary, spot news, continuing coverage, newscast, and overall excellence categories.