Custom Group in Webi 4.0

Hi,

I am just wondering if the below scenario is possible in Webi reporting

There is a dimension/characteristic called "Business" with the following values

a

b

c

d

I would like to create a customer group out of the above values such as below

a=a

b=b

c=c

d=d

e=a+b+c+d

f=a+b+c

Can this be done? If yes, any advise on how to create it is much appreciated. Thanks.

Env: SAP BI 4.0 SP6 / Windows

Regards,

Antonio