You can simply add an entry in your menu.lst for the new distros.
All you need is kernel, initrd & root-partition, here's a sample:
Code:
title Debian GNU/Linux a5, kernel 2.6.26-2-686
root (hd0,1)
kernel /vmlinuz-2.6.26-2-686 root=LABEL=Deb ro vga=791
initrd /initrd.img-2.6.26-2-686
title Linux Mint
root (hd0,1)
kernel /vmlinuz-2.6.39-2-amd64 root=/dev/sda5 ro
initrd /initrd.img-2.6.39-2-amd64
This works if you have a separate boot-partition and copy kernel and initrd to it. If not, simply point to correct partition:
Code:
title Linux Mint
root (hd0,4)
kernel /vmlinuz-2.6.39-2-amd64 root=/dev/sda5 ro
initrd /initrd.img-2.6.39-2-amd64