subtotals on specific columns

I am struggling with what should be a relatively simple issue.  In Excel, using Power Pivot or a pivot table, I can select which columns where I want subtotals to appear.  I have a measure that sums financial values with filters.  The rows in the table are organized using a financial coding dim table that has several tiers for organizing financial data.  For instance there is a sort column that organizes the data into a specific order (that matches the client's current reports), a high level category like "Income", a second tier category such as  "rental income" and then a 3rd tier which breaks down the rental income by cost or accounting code.  I want to subtotal by the 2nd tier only but when I select the subototal for rows I am getting either a subototal for each cost code or multiple subtotals.