Table of contents?

Hi all, 

maybe I'm missing something too obvious...

I'm trying to get an automatic table of contents on longer articles - like offered by e.g. mediawiki. 
This means: Whenever I have more than 5 headings in the article, I would like to show a table of contents on top of the article. 

Currently we use the HTML and manually add a table of contents to the HTML source code. This is not the most efficient way to handle this. The usage of content blocks will anyway stop this as there will be no full HTML export any more. 

Any ideas how to get this? Or is this an enhancement request?