In exactly the same way as for a single title it is possible to specify individual CSIM targets for each of the title columns. This is accomplished by specifying an array for both the target and the alt text instead of a single string as arguments for SetCSIMTarget() The following code snippet shows how to specify that.
$bar
->title->SetCSIMTarget(array('sometarget1.html','sometarget1.html'),
array('alttext1'
,'alttext2'));