Scaling With A Matrix

Hey,
this question is a follow up of a question I asked in a different forum, so sorry for the kind of double posting but I didn't get an answer for the other post, so I will try again here.

I need to scale my whole scene in a way that imitates the frustum of a perspective camera. I got as an answer that I could do that with a matrix. But I don't know how. I assume that it is something that needs MEL scripting.

Does anyone know how to scale/deform my scene with a matrix?

Thanks!