I have an idea.

Can I put different live cds all together in a dvdr and it allowed me to select which os want to boot ?

because I want to customize different os for different purpose to control the overall bootup time.
e.g. one os customized for server use i.e. no x window, no kde, gnome, etc
one customized for multimedia use
one customized for network admin use i.e. only network tool is available