See page 3 of the paper in the "Kubuntu Gutsy (V7.10) for an example of how to configure your dedicated GRUB menu.lst for each Lx ops.
With respect to adding new distro's / versions, I have found it easiest to just let the installer do it's thing with respect to GRUB. After you've installed, do a GRUB adjustment back to your dedicated menu.lst with the instructions on page 7.
Hope this helps,
Linux'd since 2005 Linux ID 422356 Ubuntu ID 15015