Need a Validation for Payroll Relationship to stop selecting irrelevant Payroll

Summary:

We have more than 10 payroll. While updating the Payroll for an employee, Users are selecting irrelevant payroll.

We want a solution to restrict in payroll relationship page (Redwood) based on Business Unit.

We have tried with existing validation rule on Redwood page, but page is not responding for the rule.

Example- If BU is "AAA" then Payroll should be "AAA".

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