How to display data from Google Sheet in a Section Header within a Google Form?

I have a Google spreadsheet that lists customers and identifies store locations for each:

Customer	Location
Customer A	New York
Customer A	San Jose
Customer B	New York

I have a Google Form that will ask the user what their customer name is (Customer A).
Based on this, I want to show a list of all the locations currently entered into the Google Spreadsheet within the Google Form as regular text.

For example, if Customer A started to use the form, it would show ‘New York, San Jose’ in a text field.

I’ve been trying to create an Apps Script to query the spreadsheet, filter the results based on the customer name, and then log the results as the description (or HelpText) for a SectionHeaderItem.

However, I’m not having a lot of luck. Most of the related questions I can find deal with how to create new questions based off of spreadsheet data, not just how to display the information.

Any thoughts would be most welcome!