Avoid page break in QTextDocument

I created a QTextDocument with a html table inside. Cells can have multiple lines of text. A bunch of rows result in one block(A block is a defined amount of rows, a block has not always the same size). I want to do page breaks only after a block ends. I can detect when a block is at end. But I dont want to do a page break after each block. How can I prevent page breaks inside a block or force page breaks if the next block is to big for the page?