How to get two text boxes for registration form segment?

I would like registrants to tell me what school and grade they are in within the same segment of the registration form. But I am only able to drag and drop one text box for each segment.
The name and password segments each have two text boxes. Name + Last Name and Password+confirm password, so how do I create the same thing for school+grade?

At the moment I can only have one segment with a text box for school and then I have to create another segment with a textbox for grade but I'd actually prefer them together.