I’ll try to rephrase this for a different response.
I would like to make openSUSE-LXDE-11.2 the 3rd OS in a multiboot linux only HD. GRUB is installed in the boot sector of the first partition. No MBR.
There are a lot of options openSUSE provides for booting, so, what option would facilitate my goal ?
It’s usually pretty good at making its own decisions and would likely choose during the installation to boot from the extended partition IIRC. But I always choose the MBR, less complicated IMHO.
I would do this: install and let it have its way. Then I would boot to the first version of Linux and reinstall that version of the bootloader to the MBR. The reason is that Grub is old and has trouble coping from far along the hard drive. Better IMHO to have it running from low down on the drive, from the first Linux.
But hey, it’s really a choice for you. Take the default if you’re a newish user.