title: Extended Module/Group Documentation in external file
body: <p>I have a maybe simple problem, but my Google-Fu produced no results.</p>
  
  <p>I have a doxygen documented header file like this:</p>
  
  <pre><code>/**
   * @file filename.h
   *
   * @date today
   * @author me
   *
   *  @defgroup mygroup grouptitle
   *  @brief my nice functions
   *
   *  Here is a medium sized description, 4-5 lines, which outline the
   *  functions and the way these functions work together, what is init,
   *  what is the main function of this module and maybe additional
   *  information on used hardware (as it is mainly embedded software).
   *
   *  Here starts another description block, typical length around 20-50
   *  lines. Detailed Hardware description, code snippets as examples and
   *  so on. I want to remove this section from the header file and
   *  replace it by something like
   *  /special_doyxgen_command_to_insert extended_doc_mygroup.md
   *
   *  \addtogroup mygroup
   *  @{
   */
  
  here are function definitions, enums, defines and what else
  
  /** @} */
  </code></pre>
  
  <p>I have no idea if this is possible but I have an additional mygroup.md in which some examples are given and and the general usage is shown. Depending on the file it has 10 - 50 lines, mostly 1 or 2 code examples.</p>
  
  <p>In the past I inserted the examples in the header/sourcefiles, but I don't like that approach, so I created a markdown file and linked to this via the doxygen ref functions.
  What I would like is a 'insert' tag that inserts the .md contend in the 'Detailed Description' Section of my Group Documentation (the HTML and Latex files).</p>
  
  <p>Is there such a command (or a set of commands to get my approach?)</p>