How to specify custom page breaks for printing the grid?

It is not directly supported, but you should be able to enable it. The key point is that all page breaks are computed in OnGridBeginPrinting(). We will try to make this more extensible in future versions, but at the moment it will work fine if you override this method.

In OnGridBeginPrinting(), all row breaks and column breaks are stored in the m_awPageFirstCol and m_awPageFirstRow arrays. So, you should override this method and store your row ids where the page should be broken in these arrays.

Take a look at the implementation of the CGXGridCore::OnGridBeginPrinting method in gxcore3.cpp for details.