Join grid cells in the same column from different rows

I tried to join grid cells in the same column from different rows, but the whole grid header disappeared.
How can I do it ?

There is HeaderRow.join(…) method, but that applies only to a specific HeaderRow. I.e. you cannot join grid cells of the body of the Grid.

It’s a pitty.

If your data has hierarchy TreeGrid may be right component to use.

Thank for your help.
I leverage TreeGrid, and my customer asked to combine cells in the header of grid, like he had done in the Excel. I managed to combine cells in two neigbour columns, but failed to to the same thing with cells in one column. BTW, I have already asked about release of TreeGrid in Vaadin 10 (Timeline 3Q) and it would be great to add this feature to the coming release :).