How to partially merge rows & cells

[piotrul]

Hi,
In my mshflexgrid I have - let's say - 4 columns.

In the last 2 rows of my mshflexgrid, I want to merge rows and columns but only within the first 2 columns.

For Example, I have last 2 rows of my grid looking like this:


And I want them to look like this:


Is this possible to achieve without adding some hidden columns etc.? I want all my data above the last 2 rows to have cells not merged.