Question about the split feature

[Malte Skoruppa]

Hi,

within screen, when I split the screen window with C-a S, what happens
is that the window gets split in two (horizontally), where the upper
region displays the currently active screen window at the time I hit C-a
S, and the lower region is empty. Then I can switch to the lower region
using C-a TAB and load any other (or even the same) screen window into
this region using various well known key combinations.

What I would like to have is that the default layout immediately after I
hit C-a S would be different.
More precisley, I would prefer it if, after hitting C-a S, the upper and
active region would display the currently active window (as it does
indeed), but the lower region, instead of displaying an empty window,
would display by default the last active window, i.e. the one I would
get to if I hit C-a C-a. When I do a split, I almost *always* when this
exact behaviour, and I always have to hit C-a S C-a TAB C-a C-a C-a TAB
to get where I want to, i.e. by quickly switching to the other region,
loading the last active window, and switching back. This is pretty
lengthy and it would be much more comfortable if I had just to hit C-a S
to get this behaviour by default.

Any ideas if there is a way to achieve this?

Thanks,

Malte