That's the way we have it implemented.
What we use to limit the amount of text shown is the headlines.
The idea is that you have a description / introduction at the top of the article, and then you add a headline then some text, and so on.
NuWiki's auto-links will show you the description/introduction up to the first headline.
If the article doesn't have a description, and starts with a headline, then we show the content up to the second headline.
If the article doesn't have any headlines whatsoever, then we show the whole article...