Conditional Logic to populate just 1 database column

Hello, in my form i need to collect which university someone has applied for but this list would be way too long so i have split it up by city. Once a city is selected it will show only the universities within that city.

I need to be able to populate just 1 column with the users selection of university rather than each set of universities being in a different column.

Ideally i think i do need the field names to be different so the data can be passed through mailchimps api and tagged so i can send a different email to people who chose different universities. (If anyone has a better work around for this then great).

But for now the main issue would be that the database (sheets) that stores the information would be too inefficient to work with because the university selection would be across 20+ columns not just 1.

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