You'll have to restore it with all 4 files.
Then, you'll need to use the DBCC SHRINKFILE command with the EMPTYFILE option to move all the data out of the file you wish to remove. You'll have to keep the primary file, so don't use this command on it! The EMPTYFILE option tells SQL not to allow data to be written to the file, and you can't remove the primary file. After all the data has been moved to the primary file, then you can use the ALTER DATABASE command to remove the extra files.
Steve