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Try making a separate base Library for each group. I've not done this as I can use a single base library. I think this is done by starting with an empty library, as if you just installed MSP. Load the songs for group 1, then make a backup, saving it as backup group 1. repeat for group 2 and save as group 2, etc. I would make a folder for MSP backups in the tablet and in another location. Then you can  restore the appropriate base library as needed. 
Someone who is doing this may be able to verify this.