Exists a tool to combine animated FBXs?

[Caronte3D]

I want to combine several FBX (one anim per file) to a single FBX with all the animations and materials.
I know it possibly can be done in Blender, but I was wondering if there's a easiest tool like a simple converter.

[Josh]

In the model editor interface, you can use the File > Load Animation menu item to load an animation from another file. Note that the model hierarchy must match exactly for this to work.

[Caronte3D]

Unfortunately that "Load animation" in the Model Editor doesn't accept FBX
I was try with a GLTF from this nice online tool: https://nilooy.github.io/character-animation-combiner/ but the Leadwerks editor hangs.
EDIT:
Ok, I can import the fbx, then convert to mdl, then use load animation.