How to maintain Items information

Hi there,

For a particular item

a) In our company's distributor's front end ordering system, they have a Sales item number. They are not aware of the JDE Inventory Item number. This sales item keeps changing every quarter for the same Inventory item. Distributors do not want to get rid of the Sales item number, they strongly want to continue using this.

b) In the JDE, they have an Inventory Item number.

What are the best practices to make sure the JDE Processes like Sales order management, Pricing, Logistics processes do not get affected by this particular model?

I have Item xref in mind to map the sales item number to Inventory item number. But the sales item number keeps changing every quarter like i said earlier.