# Remove bibliography headings with multibib and tocbibind

I use multibib which creates two families of citation commands: pri and sec. I would like to get rid of bibliography headings for the \bibliographypri and \bibliographysec commands while keeping the Bibliography heading for the main \bibliography at the end of the document. I also use tocbibind, as advised here, to include Bibliography in the TOC and have a correct PDF bookmark.

I renew thebibliography environment to remove the internal \chapter code before \newcites and then restore it to get the main bibliography right.

In the following MWE, using tocbibind modifies \bibliography in a way that it adds an empty PDF bookmark at the chapter level, which I don't want. Moreover, citations that should be on the same pages as sections Primary and Secondary are two pages farther than expected.

\documentclass{book}
\usepackage[resetlabels]{multibib}
\usepackage[nottoc]{tocbibind}

\makeatletter
{%\chapter*{\bibname}%
%\@mkboth{\MakeUppercase\bibname}{\MakeUppercase\bibname}%
\list{\@biblabel{\@arabic\c@enumiv}}%
{\settowidth\labelwidth{\@biblabel{#1}}%
\leftmargin\labelwidth
\@openbib@code
\usecounter{enumiv}%
\let\p@enumiv\@empty
\renewcommand\theenumiv{\@arabic\c@enumiv}}%
\sloppy
\clubpenalty4000
\@clubpenalty \clubpenalty
\widowpenalty4000%
\sfcode\.\@m}
{\def\@noitemerr
{\@latex@warning{Empty thebibliography' environment}}%
\endlist}
\makeatother

\let\thebibliographyold\thebibliography
\newcites{pri,sec}{{},{}}
\let\thebibliography\thebibliographyold

\usepackage{bookmark}

\begin{document}

\frontmatter
\chapter{Abstract}
\chapter{Sources}

\section*{Primary}
\bibliographystylepri{plain}
\bibliographypri{bibliography}
\clearpage

\section*{Secondary}
\bibliographystylesec{plain}
\bibliographysec{bibliography}
\clearpage

\cleardoublepage
\pdfbookmark{\contentsname}{Contents}
\tableofcontents %% Skip from TOC, only PDF bookmark

\mainmatter
\pagenumbering{arabic}
\chapter{Chapter A}
\section{Section A}