one model how to use multiple texture with jpct-ae

Question

one model how to use multiple texture? i have one obj model contain house and grass , how can i setTexture use house texture and grass texture for this obj model ?

TextureManager tm = TextureManager.getInstance();
Texture houseTexture = new Texture(LoadAssets.bitmap1);
Texture grassTexture = new Texture(LoadAssets.bitmap2);
tm.addTexture("houseTexture", houseTexture);
tm.addTexture("grassTexture",grassTexture);
house=Object3D.mergeAll(Loader.loadOBJ(LoadAssets.loadf("houseMultiMaterial.obj"),LoadAssets.loadf("houseMultiMaterial.mtl"),2));