For entering property tax on your federal tax return, it doesn't matter which home you consider your main home. All the property tax that you paid gets added together, and only the total appears on your tax return. TurboTax just asks about your main home and additional homes to try to make sure you don't forget anything.
If there is a deduction or credit for property tax on your state tax return, it might have different rules about what you can include. The rules would be different for each state.
