If I understand correctly, you would like to install three independent versions of SUSE 9.3 on your HDD? In this case I would create at least four partitions, one for each system and a shared swap. You may also share a common /home (so 5 partitions) or more.
You may install grub only for the first installation and add the two other systems later to /boot/grub/menu.lst:
Code:
title Linux1
kernel (hd0,0)/boot/vmlinuz root=/dev/hda1 desktop showopts
initrd (hd0,0)/boot/initrd
title Linux2
kernel (hd0,1)/boot/vmlinuz root=/dev/hda2 desktop showopts
initrd (hd0,1)/boot/initrd
title Linux3
kernel (hd0,2)/boot/vmlinuz root=/dev/hda3 desktop showopts
initrd (hd0,2)/boot/initrd
There are probably more and better ways for realizing this, but this is my suggestion.