combine fields in section editor

I am putting together a multi-field section editor and I want separate fields for phone area code, prefix, and number. However, in the input for my customer to add new items I would like for the screen to look like this:

(xxx) xxx-xxxx except, where the x's are I want the empty field for entry. So I want it to be lined up horizontally in one row instead of vertically.

I have the fields created, and I'm getting the characters before and after the field, I just don't know how to make it display it horizontally.

Thank you.