How to combine DITA topics AND have nested topics in HTML output?

Question

This is similar to a previous question that I asked, with one variation. I would like to know how to merge multiple topics into one (using @chunk) and then have other child topics that can be navigated to in the HTML output:

Real-world example: http://docs.autodesk.com/3DSMAX/15/ENU/3ds-Max-Help/files/GUID-484B095B-1229-4CB9-BC53-952AC40F67C2.htm

• At the top of the document you will notice that multiple topics have been combined into one. These topics include concept and task types.
• Towards the bottom of the document you will see that you can navigate to child topics.

Despite many efforts I cannot get the nested topics to remain individual. They either merge with topic1+topic2+topic3 or they disappear from TOC altogether.

Given that there are 7 individual topics of assorted types, I would like to write a map that produces the following HTML output:

• topic1+topic2+topic3
  • topic4
  • topic5
    • topic6
• topic 7

Answer 1

Okay, after a lot of tinkering I have found that the following generates the desired output:

<!-- chapter.ditamap -->
<topicref href="objects/overview.dita" type="concept" chunk="to-content">
    <!-- topics to combine with parent -->
    <topicref href="objects/visualising-objects.dita" type="concept"/>

    <!-- changing-the-object-size.dita = nested topic -->
    <topicref href="changing-the-object-size.dita" type="task" chunk="to-content"/>
</topicref>

or another slightly cleaner markup (imo):

<!-- chapter.ditamap -->
<topicref href="objects/overview.dita" type="concept" chunk="to-content">
    <!-- topics to combine with parent -->
    <topicref href="objects/visualising-objects.dita" type="concept"/>

    <!-- changing-the-object-size.dita = nested topic -->
    <topicgroup>
        <topicref href="changing-the-object-size.dita" type="task" chunk="to-content"/>
    </topicgroup>
</topicref>

This generates 2 HTML files, one for "Overview + Visualising Objects" and another for "Changing the Object Size" which is nested within "Overview + Visualising Objects".

Unfortunately I cannot place the combined topic into its own separate map:

<!-- chapter.ditamap -->
<!-- objects.ditamap = combined topic -->
<topicref href="objects.ditamap" type="dita">
    <!-- changing-the-object-size.dita = nested topic -->
    <topicref href="changing-the-object-size.dita" type="task"/>
</topicref>

(any ideas guys?)

But, at least I have found a solution!