I would like to put some extra merged cells for grouping reasons on the top of my table header.
I found something similar to this, answered in thislink from this forum, but also what I need exactly seem to be here that is not answered (.NET) link2. So If I am not clear I attach a picture of what I would like to appear.
I have the columns and I need to make appear these super-columns that I have drawn in the picture.
Any help?