>>I believe Filegroup can have multiple files.
>
>That's what I think as well. It is quite confusing however that SSMS lists both in reverse.

In the link I gave you earlier:

------------
How can I add files to a filegroup?

ALTER DATABASE CustomerDB_OLD
ADD FILE
(
NAME = FG_READONLY1,
FILENAME = 'C:\CustDB_RO.ndf',
SIZE = 5MB,
MAXSIZE = 100MB,
FILEGROWTH = 5MB
) TO FILEGROUP FG_READONLY;
GO