David,
You can do INDEX ON expr TAG tag OF MyIndex.Idx
This creates a non-structural index. I recently found out that if you have a file with no structural .CDX file opened shared, that one user can create a structural tag (even though it's currently in use). However, when someone else attempts to open the table, they get an error because it now wants to open the CDX file as well (which is opened exclusively, because it was just created).
Watch out for that!
Mark

Actually, the preferred way of getting sorted data in a shared environment is to SELECT...ORDER BY... into a cursor.

HTH!
Mark

>Is a way to index a table while i have the table shared open
>
>thanks,
>
>dave