UV texture shifting

Does someone have an example (or know a way) to blend two texures on a model, where each texture is u/v shifted over time by different ammounts? Using mtlMatrix, you can texture shift one of them, but you'd need a second matrix to be able to shift the second, and we only have one matrix to play with. Does anyone know of a way to do it differently?

Edit: Oh, and to do this with the FFP only, so no vertex shaders.