My wife and I are currently traveling in Ireland and will be looking to bring back whiskey for ourselves, friends, and family. I understand the personal exemptions are 1.14L/person. Let’s say as an individual I bring back 3 570ml bottles priced at $50, $80, and $100 CAD, for example. 2 of those bottles will be exempt under my personal allowance, but I will have to pay duties on 1 of them. How does CBSA determine which bottle I pay additional duties on?

Edit: Entering through Ontario