This feature is already present in almost all the transactions. But what would be the right implementation strategy or the strategy currently followed to populate the item UOM on selecting and item.
Would be helpful if some pointers are given to the existing implementation.
There are three fields in the item master. Stock UOM, Default Purchase UOM and Default Sales UOM. If you set this fields appropriately, the UOM should bet auto-populated depending on the transaction.
If you have to use the same Item Code (you should consider having different item codes for B2C and B2B) you can use scripting to achieve this. I’m not a developer, but others here can help you how, if you need assistance.