Multiple Desktop Environments on ubuntu Server

[lifeheart]

Hello everyone

I would like to know if it is possible to run multiple Desktop Environment on one system.

what I want to do is the following

I want to have a server running full ubuntu Gnome Desktop Environments

so I will put


sudo apt-get install ubuntu-desktop

now I want also to have another environments which is minimal GUI just to run GUI application when I need it


sudo apt-get install xserver-xorg xorg

now is there any way I can switch btween the two

with out rebooting & without opening new session.

becouse this is a server and I don't want to open more than one session at a time

Thanks

[lifeheart]

any one ...