Interfund Balancing segment - Invoices in AR

Can anyone please explain the concept of Interfund Balancing segment for invoices generated from AR

We are generating invoices from AR for a specific activity using a distinct fund number and line item - however the interfund balancing segment in GL seems to combine these invoices with invoices generated in oracle grants module and they are not being shown seperately.

Does the bank account set up have anything to do with the interfund balancing here. There is one single bank account. Should the bank accounts be set up seperately and set up as non pooled accounts ?.

Please advise.

Thanks