TomG

Don't believe you can. However in Explorer you can arrange to view files by
file type which would separate XL files from DOC files and any other type in
that folder.

You need to have 'type' as one of the categories set-up before you can do
this.

Change your folder view to either Details or List.
Right-Click the 'Name' at the top.
Tick the 'type' category
Now Right-Click in a bit of white space and choose Arrange - by type

Hope this helps