Most modern Linuces are going to have the same version (0.97) of GRUB. You can install GRUB from any of the Linux installs---and set it up to point to whatever directory you choose (for config and stage files)
From any Linux:
grub starts the grub shell
root (hdX,Y) tells GRUB where to find the /boot/grub directory with the config and stage files. (Again, this can be any of the Linux installs) If /boot/grub is on--eg--/dev/hda4, then you would enter (hd0,3) (grub counts from zero)
setup (hd0) puts grub in the mbr
You should be able to simply copy the grub.conf (aka menu.lst) file to the directory which is the the new grub "home base"