How to deal with a complete organization restructuring?

Our finance group has developed a new organization structure which would require us to create new business units and divisions. The HR team has decided that they do not want to use positions after going live with ORC which resolves one issue, but the business units are also tied to the departments which based on my research cannot be changed even with HDL. I think that this means that we would need to create new departments and assign to all employees. And I also think that this means we would lose any historical reporting abilities based on business units, divisions, and departments.