What am I missing for this validation rule? you can only put product 789, 1011 and 1213 to your order if product 123 and 456 is ordered too
AND( OR(Product2.ProductCode == "123", Product2.ProductCode == "456"),
NOT(OR( Product2.ProductCode == "789", Product2.ProductCode == "1011", Product2.ProductCode == "1213")))