$assigneeID = CRM_Utils_Array::key('Activity Assignees', $activityContacts);
$targetID = CRM_Utils_Array::key('Activity Targets', $activityContacts);
$sourceID = CRM_Utils_Array::key('Activity Source', $activityContacts);
$assigneeID = CRM_Utils_Array::key('Activity Assignees', $activityContacts);
$targetID = CRM_Utils_Array::key('Activity Targets', $activityContacts);
$sourceID = CRM_Utils_Array::key('Activity Source', $activityContacts);