Request for adding support for multiple print areas.   GemBox.Spreadsheet offers an API for setting a print area on each worksheet, with a SetPrintArea method: https://www.gemboxsoftware.com/spreadsheet/help/html/M_GemBox_Spreadsheet_NamedRangeCollection_SetPrintArea.htm

On the following link there is a sample which demonstrates how to set worksheet's print area:

https://www.gemboxsoftware.com/spreadsheet/examples/excel-print-title-area/104

Currently this method supports setting only a single cell range as a print area.