Changing Hierarchy on Bound Grid

I am looking for a way to change the hierarchy levels at runtime based on a user's selection. When I try to change them with the same code I used to create the original, the call gridBinder.AddRelation(Relation) returns nothing causing errors when I try to use the HierarchyLevel it returns. It works fine the first time through, but fails when I try to change. Any help would be appreciated. peter

In 1.6.1.x, there is a grid.Binder.ResetHierarchyLevels that you can use to clear the existing levels.