How to accept only last X entry

Hi, I want to pass to download client only X accepted.

So I tried with:

tasks:
  mytask:
    limit:
      amount: 3
      from:
        rss:
          url: file:///tmp/rss/ZTJjZGM4.xml

But this parse only 3 items on the xml.
I want to parse all file, so e.g. there’s 20 accepted, then pass only 3 (first, last, random is not important) to download client.

Do you think is possible to do that?