Both Grub and Lilo can be used as chain loaders, I use lilo and when I install a distro to my test partition I install lilo to the root of the partition, I have an entry in my main lilo.conf as follows to chainload the second lilo,
Code:
other = /dev/hda6
label = test
You set the delay to zero on the second boot loader for instant boot and set a delay of whatever if your into testing development kernels.