Problem opening Excel file 1 time with embedded Word objects
 

I have an Excel workbook with ~20 embedded Word documents (embedded as
icons; not linked). The Word documents are read-only; Excel is just
acting as convenient container for distributing this group documents to
staff. Each user receives a copy of the file (no sharing). The first
time a user views the file, it works fine - the user can record data
in spreadsheets, view the embedded documents, save and close the
workbook. However if they open the workbook a second time without
restarting their computer, they receive the "locked by user" dialog
that indicates the file is locked for editing and may only be viewed by
clicking the notify button.

How do I ensure that any open processes, threads, etc. terminate when
this workbook file is closed?