Yes, so that seems the way to go. Like you say, have one index for the entire website and one index for each user (invoices).
You specify the index to use in Javascript
Code:
<script type="text/javascript">
keyotiSearch.indexDirectory = "~/myindexdirectory";
</script>
So you can switch that to the user's invoice based index, if you want them to search just invoices and get autocomplete just for their invoices. Or you can switch the path to the entire website index for general searching.
As you can see, there is a restriction that only one index can be searched at a time, or used for autocomplete data.
Please let me know if any questions
Jim
-your feedback is helpful to other users, thank you!
