With PrE, you cannot. The Main Menu will doo a Play All, or lead to a Scene Selection Menu, where the Chapters can be played.
Now, you could easily do what you want in Adobe Encore, but it only ships with PrPro now, or a full-featured program, like Sony's DVD Architect.
PrE is limited in it navigation, and one really only gets a very few choices, such as AutoPlay (no Menu), or the common Main Menu, leading to a Scene Selection Menu. That is about all that one can do.
It depends on what template you use. Some of them allow up to four selections on the main menu. What version of PRE are you using? I vaguely recall that some PRE7 templates had up to six buttons on the main menu..
Insanity is hereditary, you get it from your children
You know, I think that you are correct, and then I will stand corrected.
You can see how seldom I author with PrE, and when I do, how few different Menu Sets I use... Duh!