Simulink using MATLAB System block: is it possible to pre-process data?

I'm coding a MATLAB System object for implementation in Simulink. The function itsel is a simple datalogger.

For the implementation, I'm using some specific MATLAB code to get the name of the input signals for the System block (gcb, get_param, etc). But, these functions are not available for code generation. As I need this code running just to fill the signals names, I'm willing to know if there is a way for Simulink to 'pre-process' this code, set a property in the System Object, and then I could use this property in the generated code?