Installments Report: Summing the installments by month, is this somehow possible?


I am trying to summarize the installments by date, so I know when they are due. Assuming all payments are made in 3 installments, I added a date and a currency field for each installment in the quotes module (see screenshot). Now I would like in a report all installments summed up by date. (See screenshot) Is this somehow possible? How would you go about this?

Any tips or ideas greatly appreciated. It seems others were looking for this functionality too. This is very common in Brazil, where over 70% of all purchases are paid in installments.