Help creating a single product with multiple Printful items

I just opened an account with Printful and I've integrated it with SS. What I want is to do is have 5 different postcards printed and sold as one product. I've created 5 individual postcard products in Printful. I was told by Printful that in order to sell them as one product I need to do that on the SquareSpace store. I don't see any way of doing that! Can anyone help??

I also need to create one store listing for multiple bundled Printful products and see no way to do this on Squarespace (I am on the basic commerce plan), which is disappointing. I even imported my Etsy listing for this specific bundle into my Squarespace shop, but there is no way on the Squarespace side to then link the listing to my Printful account for fulfillment, so I had to delete it. Please establish a way for us to be able to sell multiple Printful products under one store listing.