Playing multiple audio files in an AGI script


I am able to stream multiple files together using $AGI->exec(‘Background’,“file1&file2&file3&file4”) . However this doesnt return the key pressed by the user when the files are being played . So, i used $AGI->stream_file, which returns the key pressed , but only plays a single file.
I need to be able to play multiple files together, and also the playback should stop the moment a key is pressed by the user, and i should know which key was pressed.
Any way to achieve this ?

Thank You

soxmix will mix lot of files in single one. Then you can play that single file.