Streamline along a line or plane

I have a 3D model of a system of permanent magnets and am trying to obtain a streamline of magnetic flux density along specific planes in my model.

In the settings for a streamline plot there is an option for positioning the streamline along a plane but the drop down menu provides no options for selecting / defining a specific plane. Is there a way for me to define my streamline for a specific plane?

Thanks for your help!

Ben