Consolidating Project Data


I am working on a project approval / tracking process that includes multiple projects, each with a separate folder. Each project includes a financial plan sheet that lists spend by period, 24 periods in total. Columns are labelled P1-P24. Based on the start date, there is a row that calculates the period (ex. P6 FY22), and a row that sums the spend for that period. This works well for an individual project, but I am struggling with how to roll it all up to look at total period spend over multiple projects. How can I consolidate this, knowing that I need to interlace the spend with the correct period at the top level? I can link each individually to a summary sheet, but if a project is postponed or moved up by a month, the data will no longer be accurate without intervention.