Need help! Moving slider index

Hi, I have 2 slides, this is the scenario, once the 1st slide hits a specific index lets say index 3, I want the 2nd slide to move to a specific index, let us say index 2.

I hope this makes sense! Thanks!!

https://www.wix.com/corvid/reference/$w.Slideshow.html

Would it be ok if I asked which properties and how to use them? Thanks!