Only pull a couple paragraphs with wpomatic?

Hi,

I am currently pulling the whole feed from a site. I have been contacted by them and they have asked that I only pull the first two paragraphs.

I use wpomatic to pull the feed. How do I make it so I only pull a certain amount of data? Is this even possible?

I also only want to do this with this one site. I don't want to make it where all my feeds only get an excerpt.

Thanks