Tablix groupby and hidden attribute for a tablix column

Question

Hi I need to groupby a column name in tablix For ex: I need to display like the following: Invoice Number |- Customer Name| - Invoice amount| - Total amount for the customer 1. Need to group-by the Customer Name and 2. The Total amount for the customer should be the sum of the Invoice amount for each Customer Name. (Basically to display the total amount to be paid for each Customer based on their all invoices) 3. There is a checkbox as "Include Invoice number" and if the checkbox is checked then the column of 'Invoice Number' will be shown in the tablix otherwise it will be hidden. How to write expression for this. Thanks in advance