Sum a sequence of dates

Hi, I have a spreadsheet with 5 years of data. The dates in column B and the amounts in column O. At the bottom I want to build a summary of what happened in each fiscal year. The fiscal year runs from April 1 - March 31st. What would be a good formula to use to capture the sum of the data for each fiscal.

Thanks,

Perhaps using indirect or normal sum function by selecting multiple sheets works here. To build a formula, will have to look into a sample data set though....