Difference between total of two sub-groups from a same column in a Matrix visualization

Dear all,

     We wanted to have a solution for getting Check value by tallying the Totals of Two sub-groups named Total Assets and Total Liabilities & Equity. Please refer the below screenshot for your understanding. 

In our matrix, we are obtaining the Total Assets value and Total Liabilities & Equity values correctly. But, there is another Total that sums all the previous subgroup totals automatically. 

Say for instance,

Assets:

Total  = 1600

Liabilities & Equity:

Total  = 1600

Total = 3200

Instead of 3600, We wanted to have a difference value, 1600-1600 = 0. We are keep trying, but failing to do. Could anyone pleas help us to achieve the expected results?

Thanks

Smita