Video export question

[Chris34961083hwcx]

I am trying to export three videos from one main one, and do this automatically, using either AE, Premiere or Media encoder. So far it looks like I cannot do this.
I am building a video that will run across three 1080x1920 screens. The final deliverables are three 1080x1920 .mp4s. Thus far I haven't found a way to crop them to specific dimensions. 
Someone suggested I export to Photoshop, then chop them up and re-export to .mp4.

Which seems a strange way to do it.

Any ideas?

Thx in advance.

[kglad]

in the future, to find the best place to post your message, use the list here, https://community.adobe.com/

p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post (like this one has already been moved) if it helps you get responses.

<"moved from using the community">

[Chris34961083hwcx]

Ah, thank you kglad!

[kglad]

(you're welcome.)

[Peru Bob]

What are the pixel dimensions of the video clips that you are using?

What are the pixel dimensions of the main sequence?

[Chris34961083hwcx]

3682x1920 (which takes into account 3 side by side videos plus the two physical gaps in between the screens)
I found a series of presets in the AE layout which came from the media company that hosts the videos.
I ended up using them to crop this file down into 3 different 1080p layouts. But i still don't quite understand how it's done.
Thanks though.