Large-scale glTF models rendering


I have hundreds of glTF buiding models.If I add all the models at the same time.The Cesium system will be very slow.

So I decide to divide the buildings into tiles by its longitude
and latitude like the imagery tiles.When I request a imagery tile,I also request the buildings in the range of this tile.

But, if the viewer range include all budldings, all the buildings will be requested, the model tile strategy will be useless.

So could you give me some suggestion to the glTF model tile strategy. And is there some method to manage glTF models with LOD process,so that we get a glTF models pyramid.