How to combine multiple node into one

[lascadeansal]

Read my code below here i have 3 3d model i want to combine this into one model

val train1: CompletableFuture<ModelRenderable> = ModelRenderable
    .builder()
    .setSource(applicationContext, Uri.parse("3d/new/Train_Cabin_01_Go.glb"))
    .setIsFilamentGltf(true)
    .build()
val train2: CompletableFuture<ModelRenderable> = ModelRenderable
    .builder()
    .setSource(applicationContext, Uri.parse("3d/new/Train_Cabin_02_Go.glb"))
    .setIsFilamentGltf(true)
    .build()
val train3: CompletableFuture<ModelRenderable> = ModelRenderable
    .builder()
    .setSource(applicationContext, Uri.parse("3d/new/Train_Cabin_03_Go.glb"))
    .setIsFilamentGltf(true)
    .build()
CompletableFuture.allOf(train1,train2,train3)
    .handle<Any?> { ok: Void?, ex: Throwable? ->
        modelNode = Node()
   }