How to set global matrix for all materials

In unity, we have Shader.SetGlobalMatix(“MyMatrixName”, matrixObject) which will get the computed matrix done in C# and expose it to the shading code.

I have some precomputed(in C++) matrices(a lot) and I want to make in available in .usf material file and do some dot products to get my result.

Any idea of how to go about to achieve this?