[Plugin: FeedWordPress] Feeds: how to create one paragraph excerpts and drop the rest?

https://cheshmandaz.org My site is a news aggregator. I am using FeedWordPress on Suffusion (in Persian language). Not all ress feeds are offering excerpts. So I have established my own configuration for excerpt length (through settings–writing/reading and a plugin called Advanced Excerpt). But the full text is still coming to my site although I am hiding it. And it’s populating, forcing me to clean up the database each weak (I am using 15 feeds). Is there any way to configure the excerpts the way that it takes only the first paragraph of the feed and just deleted the rest without keeping it? Any idea? I’d appreciate this great help. Thanks, Cheshmandaz