you will need two flags to set customer groups as to what category they are in
//A
if field.attribute='A' then 1
//B
if field.attribute='B' then 1
sum each of these at the customer level
sum(@A,customerid)
sum(@B,customerid)
now you can use Running totals with evlauation formulas to all of your values per customer where they fall into one of your 3 categories
all 3 running totals are the same other than the evaluation formula (and RT name)
name=SumAonly
field to summarize=revenue
type=sum
evaluate=use a formula
sum(@A,customerid)>0 and sum(@B,customerid)=0
reset = never
use in report footer
repeatr the other two but change hte evaluation fomrulas
//for B only
sum(@A,customerid)=0 and sum(@B,customerid)>0
//for A and B
sum(@A,customerid)>0 and sum(@B,customerid)>0