How to set a special calendar for Invoices Due Dates in Oracle Receivables?

We have a significant customer who pays their invoices 70 days after issuance on specific days of the month (the 1st, 10th, or 20th). To reflect this, we have created a unique calendar with the following rules:

1. If the calculated due date falls between the 1st and 9th day of the month after the 70th day of issuance, the actual due date is the 10th. 

2. If the calculated due date falls between the 10th and 19th day of the month after the 70th day of issuance, the actual due date is the 20th. 

3. If the calculated due date falls between the 20th and the last day of the month after the 70th day of issuance, the actual due date is the 1st of the following month.