I have been able to use the method at this web address to hide used
validation list items of a single list, www.contextures.com/xlDataVal03.html.

Dropdown List Example:
SI-01
SI-02
Si-03
etc.

When SI-01 is selected from the dropdown (DD) list, it is no longer
available in the DD list and, thusly cannot be selected again by mistake.
Perfect.

I want to have multiple lists such as:
SI-01 PR-01 CCD-01
SI-02 PR-02 CCD-02
SI-03 PR-03 CCD-03
etc. etc. etc.

and when I input "PR" into a cell, only the "PR.." list is available in the
next cell DD list. I can do that too by using the method found at
www.contextures.com/xlDataVal02.html.

The problem is, when I use the "DataVal02" method, it does not eliminate the
"PR-01" (when previously selected) from the DD list the way the "DataVal03"
method does. I need the hide feature of "DataVal03" in the multi list feature
of "DataVal02". Can anyone help?