Trading 2 Devices to purchase a new iPhone SE

I'm planning to buy the new iPhone SE. I want to trade an iPhone 8 and old iPhone SE for the new one. Buying a phone only gives the option to choose 1 device to trade in, wish I could select add another device. Is there a way to trade in 2 older iphones at the same time. I know I can trade for two separate Apple gift cards, but I don't want to wait weeks to get the gift card and risk having to wait for the new iPhone SE to be restocked, and would rather trade for credit towards the purchase when I pre order it on 4.17