Auto Pay by OPEN BALANCE PER Transaction Code Merged

We need to be able to process payments by Open Balance per transaction code. The current settings are not specific enough. I may have multiple charges on dancers' accounts but want to run not just whatever is less. Sometimes I need to process just a specific payment for a group. And I would like to be able to charge whatever amount is unpaid for each family but just run one transaction. I need to be able to run for "unpaid balance with "Transaction Code". This way if a family has $300 charges for "EVENT" or "TEAM FEES" but has paid a $100 cash deposit, I can run everyone's balances for that specific code on the day its due. Almost always this is not fitting into "tuition or balance whatever is less".