I would like this to occur in the same dashboard. Sort of similar to a pipe command between panels.
Here's what you need to do to accomplish that
<dashboard>
<row>
<panel>
<chart>
<search id="baseSearch">
<query>search for the first panel</query>
</search>
......
</chart>
</row>
<row>
<panel>
<chart>
<search base="baseSearch">
<query>add segments here</query>
</search>
......
</chart>
</panel>
</row>
</dashboard>
Beware of limitations to this approach
http://docs.splunk.com/Documentation/Splunk/6.4.3/Viz/Savedsearches#Post-process_limitations