Manitra,
This is not possible. The PDF renderer that we use does not support this. This would involve splitting the data into multiple tables that fit exactly (or most of) the page and then include subtotal calculation. Rollbase generates HTML content which is then passed to the PDF renderer and that takes care of splitting tables over pdf pages (currently supporting smart table breaks which re-renders the header row for the part of the table in new page).
The subtotal calculation logic lies with Rollbase while rendering calculations lie with the PDF renderer.