Creating PDF bookmarks in custom order

Question

I use hyperref to create clickable PDF files. I have sections and subsections and they are all nicely in the PDF bookmarks. Now there are certain items in my document that I want to appear in the bookmarks but not within the hierarchy of the sections, because this is rather like a short glossary. Like the most important theorems in alphabetical order. I know I can create custom bookmarks using \pdfbookmark. They appear and clicking them puts me to the right page but they appear right where their page number puts them in the order of sections.

1. How can I decide where the bookmark appears? I would like to have them below the regular ones and ordered alphabetically (I can do the ordering myself once I know how to assign positions).
2. Ideally even: create a dummy bookmark called "glossary" where clicking does nothing but which has all the ones mentioned above hierarchically below it, so one is not overwhelmed by the number of bookmarks when one first opens the document.
3. And even further: I usually use hyperref with option bookmarksopen=true, is it possible in my new scenario, to have all the regular bookmarks open, but the glossary one closed? that would be the dream state for my document.

Answer 1

Adding bookmarks in "random" order is easy. But I don't know how to add a bookmark without action. Using a not-existing destinition doesn't look very clean to me.

\documentclass{article}
\usepackage{bookmark}
\begin{document}
 \bookmark[dest=None,open=true]{Open}
 \bookmarksetup{rellevel=1}
 \bookmark[dest=a]{A} %
 \bookmark[dest=b]{B}


 \bookmark[dest=None,startatroot,open=false]{Closed}
 \bookmarksetup{rellevel=1}
 \bookmark[dest=a]{A} %
 \bookmark[dest=b]{B}

b\hypertarget{b}{}%

\newpage
a\hypertarget{a}{}%
\end{document}

Edit: I asked Heiko about the "dummy" bookmark. His answer:

I do not know an official way (if there is any). Candidates: * named action with non-existing name * empty javascript action * an empty action object? * ...

And standards such as PDF/A might forbid much of the fun.