Sharing data among parallel scripts/functions

Hello. This is my first MATLAB post. I'm an infrequent user but I've inherited some code to which I need to add functionality. The code consists of a .m file that calls either other .m files or Simulink models based on user input. I need to add a script or function that runs in parallel with the main .m file, and is able to send data to the workspace of the main thread (so the variable is visible to Simulink). I did a forum search and read some of the documentation on parallel processing but it's not clear to me how to do this, or if it can be done. Any ideas would be appreciated. I do have the parallel computing toolbox.

Thanks, -Jamie