GameBase works by the filenames and more specifically the last character for recognising more than 1 disk.
So if disk 1 is called Game_Disk1.zip it will look for and automatically insert Game_Disk2.zip Game_Disk3.zip etc. Letters will work also i.e. DiskA.zip DiskB.zip
TOSEC names like (Disk 1 of 2) and (Disk 2 of 2) won't work.