Page Options - Pivot Tables

Hi,

I have a report with stock information, but I want to be able to cut the view depending on the business area and then a sub-area. For example; Only stocks for Agents in region1. I have created a pivot table and put the Area and Subarea in the 'Page' section of the layout. The problem is that I only want the sub-area to give a list of options based on what was selected as the business area, in the first dropdown box. Can you do this? I chose the pivot table option in the first place so that I can then subtotal the displayed data by another field, 'plant'. I am wondering if the best way might be something outside pivot tables?

Thanks

Unfortunately this is company software, so I cannot upgarde our version of excel!