trouble to separate one combined obj to a set of individual objs then to gltfs

here is my steps, help me
1、objdatas = loadObj(obj)
// try to assemble a set of objs whit the objdatas
// objs =[]
objs = splitObjdatas( objdatas )
// try to transform obj to gltf one by one
for obj in objs
createGltf ( obj, options)
writeGltf ...
2、i get the right set of models/gltfs/glbs, but i found the gltfs'textures have wrong performance except
the first one.
3、i guess the textures properties made with the index of node, but i can't find how it work, please give me some suggestions
4、the final goal is to transform one combined obj to 3dtiles with a set of .b3dm.