How to create relationship between BPA and parent contract (Enterprise Contract) - data migration

Summary:

BPA can be generated from Enterprise Contract Fullfillment lines. We need to create a such relationship during data migration.

Is it possible ?

Content (required):

How to proceed ?

Option 1 :

1 - Migrate from one side Enterprise Contract

2 - Migrate from another side the BPA

3 - Create the relationship betweeen Contract and BPA (how this relationship can be integrated ?)

Option 2 :

1 - Migrate only the Enterprise Contract

2 - Generate BPA from fullfillment lines

Is there any other way to proceed ? What is the best practice ?

Thanks and regards

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