Think of it like this. Each of the screens you want to interlock are just bytes. Each screen is ONLY a stream of bytes. So let's say you wanna go from left to right. Take your hex editor, and move the boundaries of the hex program so that you see 32 bytes horizontally across the screen for each row. Copy and paste all those bytes, so that you have 32 bytes on each row. After that, open the next nametable in the hex editor. Grab the first 32 bytes, and place them IMMEDIATELY after the first set of 32 bytes from the prior nametable. Now do the same thing for each successive row. That way you have the "nametables" aligned and right next to each other. Leave a whitespace in between each one so you can actually visualize it by looking at the code/bytes. Like this (notice the whitespace):
.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00, $00,$00,$00,etc. for 32 again...
I did something similar to this in my Rise of Amondus code... separated the tables so that I could visually picture it (this is in metatiles, but the same concept applies):
https://github.com/SlyDogStudios/riseofamondus/blob/master/includes/bankFixed/amondus_levels.asm
Now, accessing this data is different than just storing it, which is what I think you're trying to sort out. When the tables are over 255 bytes in size, you need to use a formula to be able to manipulate the data or read it. I got this formula from Kevtris years ago, and like he did, I'll leave it to you to sort it out. It helped me a ton, and I'm sure it will help you too. I'm gonna try and attach it, but I'm new here, so I dunno if it will work haha