Get correct QGraphicsItem

Question

I have a custom class derived from QGraphicsItem. In that class I have private data member which is QGraphicsSvgItem. In my custom class constructor I am creating a QGraphicsSvgItem and its parent as my custom class. Below what I did.

class CustomItem : public QGraphicsItem
{
   private:
      QGraphicsSvgItem *svgItem;
}

CustomItem::CustomItem()
{
   svgItem = new QGraphicsSvgItem(fileName,this);
}

Besides this I have another class(CustomItem2). With this class I am filtering CustomItem events.(I set all my CustomItems parent as CustomItem2)
When CustomItem2 filters an event which belongs to CustomItem i can't get information about CustomItem because the watched object returns as QGraphicsSvgItem.
But i want the object return as CustomItem.
How can I solve this?