Do I understand you correct that you are using 'Module Pool',
So you are using a PBO module to fill your ALV (controls)
Why don't you use a PAI module to check the retun code ( function executed )
Then you can use statements like
- 'SET SCREEN ...' ( for example SET SCREEN 0)
or
- 'LEAVE TO SCREEN ... ' to go back to the desired screen.
To know what function is behind the 'back' button, you can have a look in menu painter or simply run it the first time in debugging.