BW modelling for Stock Report

Dear Experts,

I am not able to construct the logic behind a business requirement. So i am posting here for your opinion and expert solution.
Scenario:

My client is using Transaction MC.9,  to check the stock  value monthly  by drilling down by Material Group, (total 35 material groups ). They download in to Excel and prepare MIS reports, Now they want BI to do that.  So  the requirement is to create a report in BI  which should tally with  MC.9 similar to the MIS report  but in the report he wants those 35 material group only  bifurcated into two divisions say 01 and 02  such  that
the report gives the output  for closing stock value, closing stock quantity  for each of these 35 material group along with
other characteristics like valuation class, Plant , material., material type

Now complexity has arose  as because in the system a particular material group has been maintained for 2 divisions say 01 and also 02 while the client requirement is to see the same material group only for one division either 01 or 02, which he has explicitly mentioned in the Excel MIS report. only and so as for the other material groups as well.

So queries:

1. how to model this scenario where material groups has been maintained in both 01 and 02 division while i need to show the same material group in only one division say 02 division and how to get the related key figures related to that material group.
* I am thinking of maintaining a custom table  and include this table in generic DS  but not sure if this will be correct or not.
And how to approach this scenario.

2.Another question:  is direct reporting on MC.9 possible in SAP BI? I have seen it has values from S031 and S032 tables and valuation class is coming from MBEW.
So how to extract the data into BI such that we can the following kind of   data records for monthly closing stock report.

Month   | Material Group|  Material  | Division|Valuation Class| closing stock quantity| closing stock value|

01.2014          ABC         PPNOPP        02      3000                   10                                   100

02.2004          CDC         LKKMAC        01      3000                    10                                   200

Any input from your end will be very helpful.

Thank You