Google Photorealistic Tiles and UrlTemplateImageryProviders

I have been exploring using Google Photorealistic tiles in CesiumJS and have successfully rendered the globe with the tiles and added vector entities to the map. I have a number of data sources, like traffic, weather, etc that I want to overlay on the map. These sources are 2D raster map tiles which I would normally load in CesiumJS using a URLTemplateImageryProvider, but I haven’t been able to understand how to combine these 2D image sources with the Google Photorealistic tiles. I’d prefer these 2D tiles to render on the terrain contour with the buildings on top, but while my 2D tiles are being read by CesiumJS (I can see them being downloaded in the network traffic, I can’t seem to get them to render in combination with the Google Photorealisitc tiles.

Does anyone know how to do this or have any sample code to show how to combine 2D image tiles with these Photorealistic 3D tiles?