Sub-category but is a link to a external website?
 

Is it possible to create a subcat which is a link to an external website?

We want a external link in our sub categories (not all, but in some dedicated places).
How can this be established?

you could add a link into the description of the main category

I'll try that.

The end result has to be something like this:
http://www.computerzaak.net/external.jpg

So you'll see the normal subcategories and next is one link to an external site.

Another but more awkward way would be to hard code some if stements to the subcategories.tpl that will display a link depending what category your in.