We use a report we export to Excell, the first page contains aggregates and then a SubReport with the details in different tabs (or pages if you export to something else).
You can do this by creating one report that contains all of the reports you want to export as subreports. Since the only way to create multiple tabs in an Excel workbook is to set a page break at the start or end of a report item, put each subreport inside a Rectangle and set page breaks on the Rectangle.