Mixing projection types in a scene

I have a 3D scene with a perspective camera and I'd like some of the elements to be projected using an orthographic projection instead.

My use case is that I have some 3D elements with attached text nodes. I'd like the text on these nodes to always be the same size no matter how far away the camera is. Is there a way I can use SceneKit to mix and match? Or is there another technique I can use?

Mixing projection types in a scene
 
 
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