A macro for changind all embedded excel workbooks in powerpoint

hi, I am working on a power point presantation which includes tens of pages with full of some charts prepared in excel then embedded to relavant page. actually all the charts has the same excel workbook. I am trying to write a macro that automaticlly change all other ebbedded excel workbooks when one of them is modified. that way when the user change one of the chart data the other charts which use same data also would be updated.
if anybody know a way to write such a macro ?