Altering Original DVD menu to include new options

Ive searched the forums and googled for an a solution to my project/question and havent been able to find what Im looking for. So anyway here's what Im trying to do :

I want to take extras (deleted scenes, alt endings etc) from lets say for example The Incredibles Disc 2 and put them on the first disc with the main movie. I want to alter the Original Menu to allow me to select the new added material. I know I'll have to reauthor the dvd since I cant just throw new vobs in and expect that to work.

Can it be done? I dont want to have to create a whole new menu from scratch as I dont have the tools or the know how to create a professional looking menu.Plus I want to keep the stock menu if possible