Intercompany AR Invoice number required to change for every financial year and with specific number

We have following business scenario and need help.

End customer sales order will book in Hong Kong OU and it will shipped from Thailand OU. And we are using intercompany drop shipment. Now in this system will generate Intercompany AR & AP invoice as per standard process. 

Now as per statutory requirement of Thailand, AR invoice number will start with one with prefix for each financial year.