Whilst still new in this framework, as of yet, I have not seen 'merging' within the table object. You can however in relation to item 2, add a row above the table, change its row theme and use that with a label to set the header.
Perhaps use page.Cell(2,1).AddComponent(lblTitle) and page.Cell(2.1).AddComponent(tblComponent)
#mytwocents untested