I'm facing following situation. I've defined two slices A and B like in the scribble. If I output this, I get a whole bunch of jpegs because A is splitted up.

-------------------
|A |
| |
| ---------- |
| | B | |
| | | |
| | | |
| ---------- |
| |
| |
-------------------

But I would like to get slice A and slice B as two jpeg-files, without splitting up slice A. So in the end result picture B should cover picture A partly. What's the best way to achive something like this?