How to keep effect between 2 segments with speed change?

If I setup my strip in 2 segments, if I apply an effect to both it smoothly goes from one segment to another. However if I change the speed on the second one, they get out of sync. I tried doing a playlist of running 1st segment, then second segment - but they seem to start simultaneously. How can I keep a smooth effect across 2 segment, but having it run more slowly on the 2nd segment?

you can not. And that is not even mathematically possible if I understand correctly.

What does the playlist feature do then? I thought it would play one effect, followed by another?