FormAPI: finding the parent of a DCT item

System

In TS6.5 FormAPI, from a DCT item, IWItem, I don't see a method provided to get to its parent item or its siblings. What if I a replicant container, each instance of the replicant has a number of children. IF the first child is a cgi-callout button, if I click on this button it would clear out all the values of its siblings? I was trying to write a onCallout event handler. But I can't find a way to know exactly which replicant instance it is when the callout even occurs.

In datacapture.cfg, I have:

<container name="parent" location="parent" combination="and" min="0" max="5" default="0">
<item name="child1" pathid="child1">
<hidden>
<cgi-callout label="Clear"/>
</hidden>
</item>
<item name="child2" pathid="child2">
<text size="40" />
</item>
..
<item name="childn" pathid="childn">
<text size="40" />
</item>
</container>

The goal is to clear out values of child2 to childn when the Clear button (child1) is clicked, and it should only affect the current replicant instance.