Menu buttons

[garrettb]

Hi. I have an application that has a few menu buttons on the left of the screen, and each one starts a movie clip on the right.
What I want to do now is have a two-level menu, where when I click on a button, it opens a deeper menu with more buttons.
The issue I have is as follows...
When I have a 1-level menu liek this:
menu1
menu2
menu3
it's easy to implements - I just define three buttons and give them behaviour etc.
But if the menu is 2-level, and when I click on menu1 I get the following:
menu1
menu1.1
menu1.2
menu2
menu3
I now have two "new button" and the buttons for menu2 and menu3 have moved.
This is probably very basic stuff.
Can anyone give me pointers on how people normally implement such a menu?
Thanks in advance,
Garrett