Grub install question?

[Ishwar Rattan <ishwar@pali.cps.cmich.edu>]

I have a debian derivative with / on hda5
that bots using grub (and is working). I
want to install another distribution on hda3,
it also asks if bootmanager (Grub) be installed
in MBR or root partition. So, will an install on
MBR destroy the boot info for the exisiting system?

-ishwar