Try a "StaticContentSample" module, with a "text" attribute (which is HTML) to include a header above your chart collections.
<module name="StaticContentSample" layoutPanel="panel_row1_col1">
This dashboard is intended to show the overall status of the
indexers in the Splunk environment.]]>
I'm not giving title for just one panel. Say there are 10 charts first 5 have something common and next five have something. SO first 5 should have one title and next five should i've another title in other words 2 sections with titles each containing 5 charts