What date is used when end dating a cross validation rule?

Summary:

How can we have 2 cross validations rules with different validation details for the same condition?

Content (please ensure you mask any confidential information):

We have a situation where we would like to end date one cross validation rule effective the last day of the month, with a different cross validation rule taking its place on the first day of the next month. The problem is that we still need to follow the original rule during the month end close process, which happens the first few days of the following month.

Example:

Rule 1 says only company A can be used with cost center Y through 6/30. Rule 2 says only company B can be used with cost center Y beginning 7/1. On calendar day 7/1 – 7/5, users will be making journal entries to the company A / cost center Y combination with an accounting date of 6/30.