How do I split a slide into two slides?

Hi!

Here is my big problem:
I have recorded the video part, than imported an audio file for the whole project.
I set the slide timing markers for the audio by hand.

Now here is my problem:
The slides have their original timings. When you set the slides' markers, you can't move them closer together than their length - Captivate won't let you do it.

But after you split the audio track between the slides, I can't seem to find a way to move part of the slide's audio to the next slide.

I'd like to make the length of the actual slide shorter, but since the audio for the slide has a fixed width, it's not possible.

So let's say:
Slide is 3 secs
Audio is 3 secs
Is there a way to make the slide 1 sec, while moving the remaining 2 secs of the audio to the next slide?

If there is no way, how do you overcome this problem?
I simply can't adjust slide timings without the audio.
But inside the project audio timing editor, you can't change the length of slides so you run into this problem...

Thanks!