Two different tables on top of each other

I need to have to seperate tables on top of each other in the same window. Different number of columns, etc. Im not quite sure how to pull that off and make the table look correct. It needs to look seamless like one table, but shifting the columns in the middle. Any ideas?

If you can afford to scroll the tables separately - then the following example should do the trick (just remove space between tables):

/examples/grid/two grids on one page.htm

But if you really want them to behave 'as a whole' - I don't see the solution, i.e. should you keep only top headers? how the bottom columns are resized, what if the total width is different etc.