Inner and Each Barcode Purchasing

We have business requirement that when we are purchasing product, we purchase with Inner Bar code item but when we are selling with Each Barcode

Lets Say. Item 1234567 is Inner Barcode of Item and its contain 50 Units and Barcode of each Unit is 7654321, We are buying from Supplier with Barcode is 1234567 but we are selling to customer in Each and Barcode is 7654321

Since both Items having different description so we place purchase order for 1234567 and also received in same item

How to handle this as we buy Different Item (Inner Barcode) and Selling to customer with Each barcode is different Item?