How to use Ribbon Groups?

 

I'm trying to implement the Ribbon gui to our existing application, but I can't figure out how to control the appearace of the Ribbon Groups.

 

In the Ribbon, a lot of parameters are set by using ordinary buttons in a radio button style, and in one Ribbon Group there is normally two, three or four groups of these buttons.

 

As there are quite a lot of buttons, I want to make sure they are placed in a logical way and not to use more space than needed.

 

It seems that in a Ribbon Group with three button groups, the first group of buttons is placed on the top row and the the second and third is on the second row - no matter if the first groups contains two buttons and the second and third has 7 buttons each.

 

In this case, I would like to know how - if I want to - to force the ribbon group to always use three rows, even if the buttons are grouped - or, as in other cases - put two button groups on the top row and one button group on the second.