How to hide a nested UIBB in an FPM OVP application ?

Hi Experts ,

    I have an FPM OVP application which basically contains the following nested UIBB's .

   a ) Main Page

             This has two sections i ) Header  ii) Items .

             In the Header section i in turn have two UIBB's .
                                      a) Form UIBB
                                      b) Composite UIBB.

                      The Composite in turn contains a  a) Master List UIBB

                                                                        b) Tabbed UIBB .

                                         The Tabbed UIBB then contains a) Tree UIBB
                                                                                        b) Chart UIBB with a drop down option . 

      I need to hide/remove the Chart UIBB based on the drop down option . I tried to do so in the   OVERRIDE_EVENT_OVP method of the controller exit class . However on selection of the event for Hiding the chart from the drop down menu on the chart toolbar . I am able to only get the UIBB's from the highest level ie i am able to get only the FORM UIBB , Composite UIBB from the header section . I am not able to drill down inside the composite UIBB > Tabbed UIBB > and lastly the CHART UIBB to hide it .

    Is there any way to get and hide the UIBB from such a nested level ? If yes , then how do i go about it ?

Thanks and Regards ,
Sheldon Rodrigues