New alternate hierarchy but no opening balances for shared members

Summary:

We have added a new alternate hierarchy that shares some of the entities from the primary (Total_Geography) hierarchy but also has some of it's own entities. We can't get any balances on the shared entities in the alternate hierarchy.

Content (required):

Prior periods are locked and we do not want to unlock as that will require us to run a consolidation, and changes in the structure of the data, new controls and invalid intersections etc, mean we'd end up with different results. How do we get the balances for the shared entities to appear in the alternate hierarchy? We are likely to need to add more alternate hierarchies as the years progress and it will not be possible for the reasons above to keep going back to year 0 to reconsolidate all the data.