The C-Script block accepts multiple, vectorized inputs. You can set the "Number of inputs" field as a vector which will specify the width of each input. Within the C-Script you can access the desired input signal using the "InputSignal(int i, int j)" macro, where the first argument is the input signal and the second argument the j'th element of the i'th input signal (zero indexed). In the screenshot below InputSignal(2, 1) would return 4.
A similar indexing approach is applied to output signals as well.