I have a post with multiple pages (pagebreak). The individual pages are displayed via sliders in the frontend.
How do I create a link that points to the anchor on page 2, for example, and opens (expand) that page.

In my example you find an anchor tag behind every pagebreak tag like this:

<hr class="system-pagebreak" title="Kontaktdaten «Vorstand»" />
<p><a id="vorstand"></a></p>