Alloy - unable to access required view elements

• app: iOS mobile
• sdk: 3.2.0.GA
• os: osx mavericks
• studio Titanium Studio, build: 3.2.0.201312191547
• output: iPhone Simulator v 7.x

I'm having difficulty understanding why I'm unable to manipulate properties of views included with the <Require> tag. I tried Tony L's answer to a similar question but it didn't help. So, I'm posting a new question. I created a new project for this use case.

index.xml

<Alloy>
    <Window class="container">      
        <View height="50dp" top="50dp" id="mainView" layout="vertical">
            <Require id="v1" src="v1" type="view"/>
            <Require id="v2" src="v2" type="view"/>
        </View>
    </Window>
</Alloy>

v1.xml

<Alloy>
    <View backgroundColor="#ece" class="container">
        <Label> This is view 1</Label>
    </View>
</Alloy>

v2.xml

<Alloy>
    <View backgroundColor="#cec" class="container">
        <Label> This is view 2</Label>
    </View>
</Alloy>

index.js

$.index.addEventListener('open', function() {
 
    $.mainView.visible = false;
 
    // $.v1.visible = false;
    // $.v2.visible = false;
});

If I run this app as posted here, mainView is hidden at launch which is the expected behavior. However, if I try this with v1 or v2 -- each being required views -- the use case fails. Apparently, there is something basic that I'm missing about required views and I'll be darned if I know what that is.

Ultimately, I plan to use this case to create a toggle that a user can switch between two required, mutually exclusive views without navigating away from the parent page. But for some reason, the mechanics of this escape me right now. I hate when that happens.

Your time and assistance are appreciated.