Merging multiple material layers into one texture

Hi, I am new to unreal and have been loving it so far as its making everything I’m wanting to do for making a 3d model of a real-life road very easy. I’m very close to finding a smooth workflow but I am trying to work out one more thing.

Basically what I’ve done so far before starting to draw in the road is import a heightmap, and then apply one of Joe Garths Brushify materials that automatically textures grass and then cliffs on slopes (sorry, I don’t know the proper term for this yet). I remove the autogen grass objects etc as I’m just needing grass and cliff textures to be painted on the landscape as pictured below.

So I’m wondering if there is a way I can create one big texture from the cliff and grass textures created onto the landscape, almost like a satellite image that I could then export and apply to an exported .fbx of the landscape mesh once imported into a program like blender etc.

I hope that made sense, I have tried searching for a way to do this but maybe my lack of terminology of these methods is the reason I haven’t been able to find an answer.