How to change textures when character exceeds a limit ?

I have made a landscape terrain in Gaea, I would like to split it in 4, as for the 4 seasons, I would like to put a shader like the winter one that covers the entire terrain, but when the character goes beyond the limits, it would progressivly fade into the next shader, for example autumn, and then the autumn shader would cover the entire piece, and then when the character goes beyond the limit, same process.
But I have no idea how to do and I don’t know what to type on google to find what i’m looking for, I imagine that it would be like a mask with 4 shaders with masks plugged in alpha linked with a blueprint function or something ? But I’m new with blueprint, I don’t know anything yet.