Well... I could make a keyword go through all the help files, but how could I know if it was found or not? It would launch all the help files you have even if the keyword wasn't found in any of those.
Another solution could be adding a key-binding to other help files (using the key binder plugin) but then you'd have to remember the combination for different help files.
An alternative could be adding another shortcut for keyword location that shows a dialog with all the help files listed. You could make a quick selection + enter (or click) to get the help plugin try it there.
Yes, I see... they're all workarounds.
To make things perfect you should index all help files.... quite a big task I guess. KDevelop does it like that and it isn't perfect too... and very slow indexing files.
Borland does index all files, and it's quite fast, but it works only with CHM help file format.
Another nice idea would be to pack all chm files in one, every time you add an help file. So you'll have as many 'chapters' as original help files, but with only one index. But again, that'll work only for chm files.
I think that the most portable thing would be to limit help files to pure html, and index all them, if I remember well there is an open source indexer for html files that works good.
BTW, you didn't choose an easy task
Ciao
Max