C:\OMG
   C:\album1
      1.mp3
      2.mp3
      3.mp3
   C:\album2
      4.mp3
      5.mp3
      6.mp3
   mp3gain.exe
   batchfile.bat

Need a batch residing in c:\omg to execute:
mp3gain /a 1.mp3 2.mp3 3.mp3
mp3gain /a 4.mp3 5.mp3 6.mp3