Menu - not motion tween but Actionscript

I’m working on a navigation in which there’s a main menu and a submenu. But I need some help here.

Let’s say I’ve got button 1, 2 and 3 as the main menu and button a, b and c as the submenu.

The idea is:
If I press on button1, buttons 2 and 3 moves to the right by 200 pixels. At the same time, the buttons a, b and c will appear between button 1 and 2.

Now, I got this working with Motion Tween, but that’s not the way how I want to do it. I think it should be possible with AS too, right? I’ve tried with SetProperty and _x, but then it doesn’t scroll to the new location.

Can anyone gimme some advice?

Thanks very much!