Linking different Reports in Webi

[kveni]

I have four different reports for four differnt levels of data. How do i link these reports in Webi. For example. From trade summary when user clicks on on a object, it has to open another detail report which is based on the object value. Like wise for four differnt values. I have been using the href links to run the fisrt report for the time that user selected. Now all the four reports have to run for same time but for user drill values.

Trade Summary
--Product
---Facility
----Item
How do i pass the drill value of the first report to second report? like wise to all the levels down?

Thanks
Veni