Variables help needed urgently

Hi guys.

I am a total noob at AS2 and I really need help with my Flash website.
I have three buttons: Button 1, Button 2 and Button 3.
I have three movie clips: About_mc, Page1_mc and Contact_mc.

When “Button 1” is pressed, “About_mc” plays to frame 50 (it eases in and stops) and when “Button 2” is pressed “Page1_mc” plays to frame 50 (it eases in and stops) and “About_mc” plays from frame 50 to the end (it eases out). I have been able to do this so far but my problem comes in with “Button 3”. When “Button 3” is pressed, “Contact_mc” plays to frame 50 (it eases in and stops) and either “About_mc” or “Page1_mc” plays from frame 50 to the end (eases out), depending on which one is visible at the time. What is happening currently, is that when the third button is pressed, both the previous movie clips are easing out at the same time but I only want the one that is currently visible to ease out, not both at the same time.

What code would I use or how would I code it so that only the movie clip that has played to frame 50 (is currently visible) will ease out and the other one will not play when the third one is easing in? I was told that I might need to use if and else statements, but I don’t know how to do that?

Thanks so much!