Jasper report: How to suppress the total column of a crosstab for specific column group

I have a cross tab with 2 column groups, the upper column group have a total column, is there a way to suppress the total column for a specific column value. for example if i have the following query:

> select employee_number, payment_type, payment_name, amount from
> employees emp inner join payments pay on emp.id = pay.employee_id

the query results will look like this:

- 1, earning, basic, 1000
- 1, earning, bonus, 700
- 1, deduction, tax, 300
- 1, deduction, other, 100

in the cross tab the following is defined:
row groups:

- employee number

column groups:

- payment_type
- payment_name

measures:

- amount

i want to display the total column group for earnings but not for deductions so the final report will look like:


----------



   **employee number    basic    bonus    total earning     other    tax**

     1                  1000     700      1700              100      300

the problem is that the total deduction appears. i haven't find any option that i know about in the studio that can conditionally show the total, may be this can be done from the API . any help is appreciated. note that i am using jasper 6.7.0