Scripted _alpha fades :(

help…

ok 5 movie clip buttons (named mc_but1 through to 5) and 5 movie clips (named mc_1 through 5),
when buton 1 is pressed movie clip 1 fades up and the other 4 movie clips fade out,
when buton 2 is pressed movie clip 2 fades up and the other 4 movie clips fade out etc etc.

this is just the script for button 1

mc_but1.onPress = function(){

{mc_1.onEnterFrame = function ()
{if (mc_1._alpha < 100)
{mc_1._alpha += 10;}
else{delete this.onEnterFrame;

{mc_2.onEnterFrame = function ()
{if (mc_2._alpha > 0)
{mc_2._alpha -= 10;}
else{delete this.onEnterFrame;

{mc_3.onEnterFrame = function ()
{if (mc_3._alpha > 0)
{mc_3_alpha -= 10;}
else{delete this.onEnterFrame;

{mc_4.onEnterFrame = function ()
{if (mc_4._alpha > 0)
{mc_4._alpha -= 10;}
else{delete this.onEnterFrame;

{mc_5.onEnterFrame = function ()
{if (mc_5._alpha > 0)
{mc_5._alpha -= 10;}
else{delete this.onEnterFrame;

}}
}}
}}}}}}}}}}}}

its clearly stupid and takes forever to do anything, please help!!!