Multiple documents, one structure

Hi, I have multiple documents that contain data from different clients. So, Client A = docA.xls, Client B, docB.xls and so on.

The documents contain a lot of pivots, and I would like to have one sheet that contains all the pivots with the ability do change the data source (that will be in different docs).

Is it possible to have one sheet with all my pivots and simply "change" the data source somehow?