How can I use Matlab Function block of Simulink into Simpowersystems?

I want to use the Matlab Function block of Simulink into Simpowersystems based three phase model. Can any one please guide me how to do this?

[Shivakumar]

I don't think your question has clarity.

Answer 1

[Joel Van Sickel]

You need to customize the block using the poewr gui custom block options:

https://www.mathworks.com/help/physmod/sps/powersys/ref/powergui.html