Typically, combining those local taxes into one entry in TurboTax works great. They are separated because the actual W2s have been sent to the state and federal taxing authorities so they already see what taxes were paid to whom. The taxpayer, when filing, typically just needs the total number to use if itemizing for the state/local taxes paid deduction.
Having said that, there are some localities that do have school and/or income tax forms that need to be filed with the state forms to reconcile those taxes paid. The separated amounts in those cases may be needed on those forms. Likely in those cases you can combine on the W2 entry and then separate/verify the correct amounts in the state/local interviews.
To ensure you are not one of those rare cases you might post what state/city/locale you are in and someone may be able to verify for you.
@tatate01
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