Customer Segments for A/B Testing Shopify Emails

[ShopZoo]

Is there an easy way to split our entire list of subscribed customers and split them into 2 unique segments/lists for A/B Testing Shopify Emails? I reached out Shopify support and they said we can add a Tag to half of our subscriber list, but we have nearly 40K subscribers, so this would take a long time. Is there an easier way to accomplish this?

[jessredbean]

Sorry that I'm piggy-backing, but did you find a solution to this?  I have the same question...