Simple distros are written to install their bootloaders only in the MBR but just about any decent Linux will allow its bootloader to place in
(a) a floppy so that it can be booted from it without the MBR assistance
(b) MBR of the first bootable disk to boot automatically from the hard disk
(c) the root partition where the Linux has been installed there, so that it can be booted by another operating system be it a Linux, a Window, Dos or BSD.
If one installs 100 distros there is only one MBR. So after the first Linux taking over it the remaining 99 distros can have their bootloaders installed in the respective root partitions and everyone can be booted by chainloading by the first one. This is standard technique and definitely the quickest and easiest. More importantly chainloading works for Lilo too by its "other=" statement and so all the Linux can be mixed and booted together by one boot loader. Lilo has a fixed screen restricting its ability to displace no more than 27 entries for booting. Grub has a scrolling screen and so over 100 distros can be accommodated.
The other method is to boot the 99 distros directly by naming the kernel and initrd files locations in the /boot/grub/menu.lst for Grub or /etc/lilo.conf for Lilo that controlling the MBR.
Within each distro you can tell Grub to place itself in floppy, MBR or root partition (Say hda7) respectively any time you please by commands
Same for Lilo with commands
lilo -b /dev/fd0
lilo -b /dev/hda
lilo -b /dev/hda7
Putting the bootloader at a location is a freedom any user can choose to suit his/her need. There should never be a need to destroy any boot loader once it is installed.