You probably have a while loop going over all the lines of the file, or even directly when you're /sockreading it.
Each time you find a news item to send to the channel, add this:
inc %cnnnews.counter
and add an extra check
if (%cnnnews.counter <= 3) {
; msg #channel News headline: %d
}
around the part that send a message to the channel.
Make sure to /unset %cnnnews.counter before you open the socket, or you won't get any news the second time
