Can I create posters with multiple designs in the same order?

No. You can only submit one unique poster design per order (or two, in case you order back-to-back posters with different designs). However, you can order multiple copies of the same design per order.

You can also do simultaneous orders for different poster designs. Try to set their estimated delivery dates and check on the turnaround times so you may receive your poster orders at the same time.