How to Allocate a Customer Payment to Multiple Customer Accounts and Invoices?

How to Allocate a Customer Payment to Multiple Customer Accounts and Invoices?

I use Netcash to collect Debit Orders for Clients to pay for certain services, I need a way to get the payments reflecting in customer accounts better. Right now, Netcash is added as one of my bank accounts in Zoho Books, so when the Netcash money comes in to my main bank account, I save the transaction as a transfer between accounts and thereafter go to the Netcash 'Bank' Account and manually add the customer payments for 20+ Customers which is very time consuming, give me a better way of doing this??