How to link Outbound shipment lines against Inbound Shipment lines

Hello!

we are creating transfer orders for which we Generate Shipment Request (ESS job). Then we submit shipment acknowledgement and shipment confirmation through "shipmentTransactionRequests" REST API (CreateAndConfirmShipment).

After that we trigger "Perform Shipping Transaction" (ESS job) in Fusion which generates Outbound shipment (based on the data we provided in "shipmentTransactionRequests" REST call) and Inbound shipment.

Now the issue is that receiving is done against the Inbound Shipment which sometimes has reshuffled lines (in comparison to Outbound shipment).

If we have a scenario where transfer order line is split into multiple shipment lines (because they have different LPNs for instance), how can we identify which outbound shipment line is related to which inbound shipment line? (As multiple shipment lines reference the same transfer order line)