SOE - Required Field Question

User is running E1 9.2.6.4.

I'm looking for a way to make a field required when a particular item is sold. They have no preference on what field is used at this point.

I was originally thinking using lot number required, but this is already a lot controlled item.

I also thought about using a preference, but wasn't sure of a field that could be used.

Government requirements are that whenever a particular item is sold, an additional number needs to be included on the order line. This number will vary depending on date, customers, items. etc.

Is there a way to have a field required based on an item number without having to customize the application? Any ideas are welcomed.