\documentclass[12pt]{article}
\usepackage{xcolor}
%\usepackage{xr-hyper}
\usepackage[bookmarksopen,bookmarksnumbered]{hyperref}
%\usepackage{eforms}
\usepackage{xbmks}

% the xr-hyper package may also be used if you have
% cross document links within the body of the doc
%\externaldocument[d1-]{doc1}
%\externaldocument[d2-]{doc2}

\title{On merging bookmarks for several documents}
\author{D. P. Story}

% The \xbmksetup command is placed in only
% one of the collection. It is written to xbmks.cfg
% in input by the other files to obtain uniformity
% of option choices.
\xbmksetup{%
  docbundle={master,doc1,doc2},
  colors={int=red,ext},
  styles={intbf}
}

\begin{document}

\maketitle

\tableofcontents

% color and style specified. This will be how these entries are displayed across 
% all documents in the bundle
\pdfbookmarkx[1]{http://blog.acrotex.net}[action={/S/URI/URI(http://blog.acrotex.net)},%
  color=magenta,style={bf}]{blog}
\currentpdfbookmarkx{http://www.acrotex.net}[action={/S/URI/URI(http://www.acrotex.net)},%
  color=magenta,style={bf}]{home}
\currentpdfbookmarkx{First page}[action={/S/Named/N/FirstPage},%
  color=magenta,style={bf}]{First}
\currentpdfbookmarkx{Last page}[action={/S/Named/N/LastPage},%
  color=magenta,style={bf}]{Last}

% the eforms versions of the above
%\pdfbookmarkx[1]{http://blog.acrotex.net}[action={\URI{http://blog.acrotex.net}},%
%  color=magenta,style={bf}]{blog}
%\currentpdfbookmarkx{http://www.acrotex.net}[action={\URI{http://www.acrotex.net}},%
%  color=magenta,style={bf}]{home}
%\currentpdfbookmarkx{First page}[action={\Named{FirstPage}},%
%  color=magenta,style={bf}]{First}
%\currentpdfbookmarkx{Last page}[action={\Named{LastPage}},%
%  color=magenta,style={bf}]{Last}

\section{Master One}

Some content goes here.

% color and style not specified, this bookmark will take on the default
% color and style as declared in the \xbmksetup command.
\belowpdfbookmarkx{JavaScript Action}[%
  action={/S/JavaScript/JS(app.alert("Hello World!\\n\\nAnnounced from the document "
  + this.documentFileName);)}]{jsa}

% eforms version
%\belowpdfbookmarkx{JavaScript Action}[
%  action={\JS{app.alert("Hello World!\\n\\nAnnounced from the document "
%  + this.documentFileName);}]{jsa}

% color and style not specified, this bookmark will take on the default
% color and style as declared in the \xbmksetup command.
\belowpdfbookmarkx{Go to doc1, page 2}[action={/S/GoToR/F(doc1.pdf)/D[1 /Fit]}]{gotor1}
% eforms version
%\belowpdfbookmarkx{Go to doc1, page 2}[action={\GoToR/F(doc1.pdf)/D[1 /Fit]}]{gotor}

\hypersetup{bookmarksopen=false}
% This next bookmark is a title only, the actions is to jump to an destination not defined
\subpdfbookmarkx{Sub: Optional Bookmarks}[action={/S/GoTo/D(undefined)}]{optBmks}
\belowpdfbookmarkx{doc1, page 3}[action={/S/GoToR/F(doc1.pdf)/D[2 /Fit]}]{gotor2}
\belowpdfbookmarkx{doc2, page 2}[action={/S/GoToR/F(doc2.pdf)/D[1 /Fit]}]{gotor3}
\hypersetup{bookmarksopen=true}

\subsection{Master One: subSec 1}

Some content goes here.


\newpage


\section{Master Two}

Some content goes here.

\subsection{Master Two: subSec 1}

Some content goes here.

\newpage

\subsection{Master Two: subSec 2}

Some content goes here.


\end{document}

