RDLC Report C# Winforms - Group by value with group sum, then group difference

Question

I wish to create a report based on a dataset with fields;

ACCNumber

ACCName

ACCAmount

I wish to group by ACCNumber where AccNumber is BETWEEN x and y, then another Group where ACCNumber is BETWEEN a and b, then ...

For each subgroup I need to display each ACCNumber with the ACCName and SUM(ACCAmount) on one line.

At the end of each subgroup I need the Total for that subgroup

At the end of the report I need the value of subgroup(1)-subgroup(2)

eg.

Income

100 Sales $50.00

110 Interest $10.00

                         Total Income $60.00

Expenses

200 Paper $20.00

210 Pens $ 5.00

                         Total Expenses $25.00


                          Profit               $35.00

At the moment I have 2 Tablix to provide the grouping solution using a Filter.

Tablix1 Filter : ACCNumber Between 100 and 199

Tablix2 Filter : ACCNumber Between 200 and 299

I have Sum values for each Tablix.

What I cannot work out is how to get the difference between these sums.

Any assistance appreciated.

TIA

John