I have created a multibody parts in a single file and then scale and creation of parting line is done.

Now I have a problem with "Shut off Surfaces". I have uploaded the model.

I have tried with Single part Everything is OK.

Now I need to know is

1) Is my approach is correct or not.

2) If "YES" how to complete / If "NO" how to approach at these similar conditions.

Thanks in advance