World (spoilers kinda)(mostly me complaining)

So I have been doing a little research into both the worlds of ATLA and Naruto, and both of the worlds are massive. Combining the worlds without having them interact for the most part is a struggle and I haven't even started.

In ATLA the countries, tribes, and air temples make up what is called the known world, which in itself means there must be parts of the world still unexplored so I'm gonna run with that.

ATLA World Map(s)(image here)

Naruto world Map(s)(image here)

Basically in my head I'm going to make it so the ATLA world is bigger and in that section of its world map that is "unexplored" im gonna slap in The countries from naruto. 

I don't really want the benders or the Shinobi interacting so maybe the naruto countries are surrounded by some big ass mountains or a natural sea wall like this is one piece or some shit idk I have to think more.

Any questions can be asked here.