Some Business needs

We are using ORACLE EBS 12.1.2 with 11.1.0.7 as database.

1. Our business needs to add multiple checks on one receipt voucher (document number). For now we enter each check with one document number. To Explain:

When we receive more than one check from a customer we give this customer one receipt voucher with all checks totals. How can we enter checks with one document number.

If you enter same document number for two checks the system will raise error.

2. Can we stop Sales Order processing based on customer aging. (If he have outstanding transactions for more than period of time. Ex. 3 Months).