Using splatmap to generate texture strings using level

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Speaking people I’m developing a RPG game world open my land will have 30 km² I will use the level streaming to render it in parts.
My land is going to be divided into 4 parts being it fire, ice, desert and wildlife. Each of these continents will have its texture combos and they will all be on the same level. Good initially to be able to texturize this my terrain with several different textures I used the world machine and generated 4 different slaptsmaps to be able to texturize all my scenery with a single material but using these splats as reference to indicate where goes ice, fire etc. But here comes the question when generating my terrain in tiles to be able to import to unreal using the level streaming he divided my terrain into several parts this is normal I know and my splats he did the same thing ie there were 4 splatsmaps one for each continent But as they were divided then it got several splats I wanted to know how do I now to create a material that recognizes where each element goes with all these divided splatmaps as shown therein in the image.

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This is my terrain and some separate splats

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Briefly speaking how can I use a splatmap to use as coordinates to texturize my terrain if there are going to be a lot of them, what can I do to be able to texturize my terrain so that each continent is with a different element.