You can certainly just send the 20 songs if you want. Go to the Songs tab, long press one of the songs to select it, tap all twenty songs, then tap Share->Export as .msf. You can then import that .msf on the other tablet. Alternatively, you can use the sync library feature to push changes betwen the devices if the libraries are identical, as that is much faster. Just tap the three dots at the top right corner of the library screen, then Sync Library->Synchronize to a device, and you can set your tablet as the server, their tablet as the client with the sync type set to "Update Client". That would push your library over to the other tablet, forcing them to match.
Mike
Mike