You can manually mount additional ones by creating remotes using sudo rclone config. Once you mount them you can have them added to the unionfs mergerfs in the PG options menu.is it any good for running a plex server? BTW, how to mount multiple team drives on one PG. It seems, that you can manage only one tdrive.
Alternatively you can install the latest rclone beta which supports Google's new shortcuts feature, then make shortcuts on your mounted team drive to the other team drives via the Google drive web interface. Note the account you are mounted with must have access to the shortcut paths.