Question on Dependent Picklists:   I currently have a dependent picklists on Opportunity object in a 2 yr old org -- the users want to change the dependency order on the fields whereby a lower level field (currently 4th in the selection hierarchy) will drive the selection on the lower and last level picklist and once it is selected the higher level  (levels 1 - 3) fields will then be auto populated based on that value.  Level 1 - Business Unit; Level 2 - Mega Trend; Level 3 - Reporting Segment; Level 4 Market Segment; and lastly Level 5 App Segment.   Odd as it may seem, is this even possible?   How will it affect the historical records and other related objects?