Controlling spend with managers who are managing multiple country specific budgets

Summary

Looking for areas to help managers control spend based on country specific budgets

Content

Our managers will have employees across multiple regions. Each region will have a different budget. However, the manager will only see one collective pool of dollars to allocate across all employees regardless of where they reside. While we will populate the target amount, what are ways other companies have reduced or eliminated the possiblity of a manager allocating dollars to an employee in a country where the budget may not be sufficient to support the allocation despite the overall budget saying the manager has the money to do so?