How to define the Market Sales KF, in order to receive the desired result

Question

Hi all,
I dont know how to define the Market Sales Kefigure, in order to get the following result. Any hint is more than welcome.
Prd_ID = Product ID
PS  =  Product Sales
M_ID = Market ID
MS  = Market Sales
MS%  = Market Share ( formula in BEX PS/MS)
<b>
Prd_ID;PS;M_ID;MS;MS%</b>
A00001;10;MRK1;100;10%
A00002;20;MRK1;100;20%
<b>SBTOT</b>;30;MRK1;100;30%
B00001;40;MRK2;200;20%
B00002;30;MRK2;200;15% 
<b>SBTOT</b>;70;MRK2;200;35%
<b>GTOTL</b>;100;MRKX;300;33,3%
Products A00001 and A00002 compete in the same market. So the individual marketshares should be calculated against the market MRK1(200), e.g. 40/200 and 30/200.
The totals now, of the A00001 and A00002 products(3040) should be compared against <b>the same market</b> MRK1(200),</b> and <b>not against</b> the MRK1MRK1(200+200).
Thanks
Vasso Siagri<b></b><b></b><b></b>

Answer 1

Maik,
thank you for your answer, but I am afraid this is not giving the desired results.
What I want----
>What am getting
Prd_ID;PS;M_ID;MS;MS%
A00001;10;MRK1;100;10%  ---> 10;MRK1;200;5%
A00002;20;MRK1;100;20%  ---> 20;MRK1;200;10%
SBTOT;30;MRK1;100;30%   ---> 30;MRK1;200;15%
B00001;40;MRK2;200;20%  ---> 40;MRK2;400;10%
B00002;30;MRK2;200;15%  ---> 30;MRK2;400;7,5%
SBTOT;70;MRK2;200;35%   ---> 70;MRK2;400;17,5%
GTOTL;100;MRKX;300;33,3% ---> 1000;MRKX;600;16,7%
Neither resticted KF restricted on Market ID is working for many markets; it is working only if you analyze one market id.
Any idea? bw idea? What actually I need is aggregation of unique records in terms on market id.