Can I mouse over a group and cause another group to do something?

Question

When I mouse over id=wholeGroup, I want group rect47 to become more visible by changing its alpha value.
Can someone help me understand how to do this? Thanks.
Here is what I have so far, but I am getting multiple errors.
1067: Implicit coercion of a value of type String to an unrelated type Number.
1119: Access of possibly undefined property mouseOver through a reference with static type spark.components:Group.
<fx:Script>
  <![CDATA[
     private function showYourSelf():void {
          if (wholeGroup.mouseOver==true) {
               rect47.alpha="1.0";
           } else {rect47.alpha="0.3";}
  ]]>
</fx:Script>
<s:Group id="wholeGroup" mouseOver="showYourSelf()" >
  <s:Group id="rect47">
      <s:Rect>
         <s:fill>
              <s:SolidColor color="0x474747"/>
          </s:fill>
     </s:Rect>
  </s:Group>
  <s:Group id="rect87">
     <s:Rect>
         <s:fill>
              <s:SolidColor color="0x878787"/>
          </s:fill>
     </s:Rect>
  </s:Group>
</s:Group>

Answer 1

Change the strings to numbers:
rect47.alpha=1.0;
<s:Group id="wholeGroup" mouseOver="showYourSelf()" mouseOut="hideYourSelf()">
In the function showYourSelf() just set rect47.alpha=1.0
In the function hideYourSelf() set rect47.alpha=0.3
No need for the if statement.