Display Order column in SharePoint list that auto updates all items when one changed

I have a document library that has a set of douments in it and I'd like them to be ordered in the library/view in a user definable way. So ideally I'd like to add a DisplayOrder or Priority column and have this set by the users. Each number in this column MUST be unique and should update other items in the list when a user "inserts" a document in the middle of the order or changes the order in anyway.

The only way I can figure doing this is to run a workflow that does the grunt work, but was hopeing that there might be an easier way.

This is all on MOSS 2007.

Thanks for any 开发者_StackOverflowsuggestions.

Other than workflow, you can have a event handler too. I don't think there is no way to force uniqueness in MOSS 2007 other than custom code.