You've shown us screen captures from Acrobat Reader. The 'table of contents' in Word is not directly related to the bookmarks which you are showing us in your screen grabs.

Saving a Word document to PDF can (if you have your options set correctly) create a hierarchical list of bookmarks which can be viewed in Acrobat. You can then use a different tool such as Adobe Acrobat to edit and add new bookmarks to make the acrobat file easier to navigate.

I think we may have missed something in translation and I don't understand German so I'm not sure what your actual aims are but I'm thinking that what you are trying to replicate is not being done in Word - it was added afterwards in Acrobat.

You can certainly have multiple TOCs in Word but the bookmarks in Acrobat ignore that and come from either the outline level paragraphs (hierarchy based on heading levels) or on bookmarks (no hierarchy). You will need post-processing on the PDF to vary from this.

__________________
Andrew Lockton
Chrysalis Design, Melbourne Australia