Delay slide show start

I have two slide shows side by side so they look like one slide show split into two images. The effect I am trying to achieve is the left image slide changes, then the right so that they alternate when they change. But no matter what I do, the slides both load at the same time with a slight delay in the second behind the first (as you would expect). Sure, I can set one to load quicker than the other, but the client wants them both to load at 5 sec intervals with the right slider loading 2.5 secs behind the left so they alternate evenly.

I wish there was a selection option for starting the slide show, but since there isn’t can any point out how I might achieve this. Cheers.

Test site here: https:// oppenheimer . co . nz / wordpress /

(Close up the gaps.)

https://www.ads-software.com/plugins/slideshow-jquery-image-gallery/