How to default Segment3 based on Primary BSV in Additional Intercompany Balancing rules setup

Summary:

We have the setup - Manage Additional Intercompany Balancing and Clearing Options – where we can create rules to balance the secondary balancing segment (in our case, it is "Fund") can be defined only at LEDGER level. As per our client requirement, we need to specify segment3 (DeptID) according to segment1 (Entity) based on our Entity and default DeptID mapping which could not be achieved here.

Please help how to proceed with this to achieve this requirement.

Please note that we have Manage Intercompany Balancing Rules setup at Primary Segment Value level where we are able to achieve this requirement but this is only applicable to balance the primary balancing segment (Entity).