I believe that RHEL installs using a Logical Volume Management (LVM) and SuSE has a straight partitioning scheme. So, I bet that SuSE did not pick up the RHEL installation.
Do you remember if RHEL was listed when you set up the bootloader in SuSE? Did you install Grub in SuSE on the MBR of disk 1, or hda?
Can you post the output of the command fdisk -l as root user in the console within SuSE?