How to load multiple periods into beg balance in EPCM

Summary: In order to have a calculated driver work in EPCM I need to add my Prior Years Year Total with the BegBalance from the prior year. We had initially loaded the data so that Dec23 = current balance. I can copy that data to BEG Balance FY24, however need to be able to add the periodic months with the Beg Balance to calculate the BEG Balance for FY25, and then do this again for the BEG Balance FY26

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