How to track On Account balance separately for each customer

Hi Everyone,

Client wants to track the On Account balance separately for each customer. It means when the customer pays money in advance without the relevant information about the transaction then the amount goes in On Account (account setup in the receipt class). At present it goes and sits in On Account GL code in the Receipt class which is same for all customers. Client wants to track this separately for each customer, maybe a different sub-account in the flexfield.

Thanks

Swapnil