To migrate the multiple PST of the user using GAMME tool ,
Maintain the Folder Heirarchy as per below.
PST |--- > Folder (name it username@domain.com)
| Place the PST under the folder
|----> Folder(name it username2@domain.com
Place the PST under the folder.
|-- Similarly for next users.
| -> userlist.csv ( Mention all the useremail ID and save it)