How to append a Lot # when transferring from 1 Whs to another?

To start off, we are on Sage 100c Advanced v2018.2

How can we append an original Lot # when transferring qty from 1 whs to another?

Create PO for Qty = 100,000. 

ROG the full Qty 100,000 to an offsite warehouse ("OFF") with Lot # 12345. 

When when we need product to produce finished good, want to Transfer say 20,000 from Offsite Whs (OFF) to On Premise Whs (ONP) and append the Lot # with an A, B, C, etc. (12345-A).  Then the next transfer append with next sequential letter (123456-B, 123456-C) until original Qty (100,000) is exhausted from the Offsite Whs. 

I don't want to transfer from whs to whs and then use Adjustment to reduce Lot # 123456 and create new Lot # 123456-A

Any suggestions would be greatly appreciated.