how to make collapse/expand on click of a particular icon in row_grouping(like plus/minus img's)

sandep

hi i am using row grouping plugin and getting data tables. every thing works fine.but i want the rows to be collapse/expand on click of "minus/plus" images(in this example you can see plus/minus img's in front of every grouped row ::https://jquery-datatables-row-grouping.googlecode.com/svn/trunk/collapsibleGroups.html ) on every grouped row but not on anywhere of a grouped row how to achieve it.can anybody help?