Thanks a lot for your reply. I only want to do this once however at the start of the simulation and also only for the blocks preceding the input to my custom block. Essentially I want to create a block that can determine the mathematical functionality (and precision etc) at any specified point in a model it is instantiated in.
Your right maybe a standard function might be better; but I just need to somehow graphically denote until which point in the model I would like this interrogation to be done. Maybe a MATLAB function block would suffice as I only need to use get_param and a few file IO functions. I would really appreciate being pointed in the right direction.