R12 Bank Statements reconciliation after upgrade from 11.5.10.2

We are in process of upgrading from 11.5.10.2 to R12. When we upgrade to R12, Bank\Bank branches and Accounts setup has changed. Due to MOAC feature in R12, we can have a single account and grant access to different organizations instead of creating the account in each organization individually.Until that point everything is fine.

Once we have only one account with multiple organizations access, how do we handle the bank statements reconcilation which consists of old Payment details too in a new statement (details before upgrade)?

Say we have 5 organizations, org1, org2 ....org5

Before upgrade we had account 1234 setup in all orgs (1 to 5), after upgrade all are migrated to R12 with a different bank_account_id automatically.