Sub-grouping?

Hello,

I would like to make a two level hierarchy with grouping, involving two different fields (one contained in another).

Like this:

- Project ABC
      - Clients
          (reports)
      - Employers
              (reports)
      - ...
- Project XYZ
      - ...
      - ...

Is there any way this is doable?

Thanks in advance,

António Caetano