In a view, see documents organised in their classes

Hi All,

We have been asked by some of our users if it is possible to have all the documents that are listed under an object (client in our case) further organised into the document classes, and not just a long list of all documents under that object. 

I know we can create views for the different types of documents, but they would like to see it under the object.

Eg:

Client

    L Documents

        L Audits

             Audit01.doc

             Audit02.doc

        L Invoices

             Invoice001.pdf

        L Quotes

             Quote0001a.xls

Any assistance would be appreciated.