Vista - Grouping by Artists with slash in artist name

I have some WMA files where the Contributing Artists in WMP11 was tagged with
an artist name containing a slash ("The World/Inferno Friendship Society").
When I view the folder containing the files in Explorer in Vista, the
Artists column shows it as two separate artists ("The World" and "Inferno
Friendship Society"), which prevents grouping by this column from working
correctly. It shows correctly as a single artist in WMP (although if I save
the data in Explorer, this causes WMP to pick it up as two artists).
Experimenting, I found that if a file is tagged with the artist as AC/DC,
this is picked up correctly as a single artist but this was the only one I
could find (e.g. even a similar name such as AB/CD is picked up as two
artists). Is there any way to force Explorer to treat the artist as a single
artist, or does it have a hardcoded exclusion for AC/DC (which if it does,
would seem absurd)?