Scientific Word/Workplace ⇒ Better indexing?

[Tech book author]

I have just completed a complex technical book. It consists of twelve chapters plus two appendices, a large number of equations, and more than 500 figures. Many topics are discussed in multiple chapters. This is my ninth book. I estimate that there will be six to ten pages of index entries. For my previous books I created the raw index separately, then entered the page references after I received the printer's proof. This book will be web based and updated frequently. Scientific Word's ability to embed index entries in the file seems to be the best way to proceed because there would be no need to update locations after the book is modified. I understand how to create an index in SW. The problem is that every entry must be retyped where it occurs, even if a similar entry already exists. Not only is retyping entries tedious, it is possible that different entries will be created for the same item because they were not entered with exactly the same wording. Consequently the ...idx file will require heavy editing. Thus, my question:

Is there an auxiliary program for creating index entries that lets you select from a list of existing items? This capability is available for cross-references in SW. If not, I think I will try to create a file of index items, then copy an item and do a word search through the subdocuments for places where the item occurs. Can anyone think of a better way?

Thanks for your attention. Any comments and assistance will be greatly appreciated.