Change Menu Item per Tab using Titanium Android

Hi I have 3 tabs inside my app.js:

var tabGroup = Titanium.UI.createTabGroup();
var nowShowingWindow = Titanium.UI.createWindow({
    title: "Now Showing",
    url: "window/nowshowing.js"
});
 
var nowShowing = Titanium.UI.createTab({
    title: 'Now Showing',
    window: nowShowingWindow
});
 
var cinemasWindow = Titanium.UI.createWindow({
    title: "Cinemas",
    url: "window/cinemas.js"
});
 
var cinemas = Titanium.UI.createTab({
    title: 'Cinemas',
    window: cinemasWindow
});
 
var upcomingWindow = Titanium.UI.createWindow({
    title: "Coming Soon",
    url: "window/upcoming.js"
});
 
var upcoming = Titanium.UI.createTab({
    title: 'Coming Soon',
    window: upcomingWindow
});
 
tabGroup.addTab(nowShowing);
tabGroup.addTab(cinemas);
tabGroup.addTab(upcoming);
tabGroup.open();

and in my nowshowing.js how can I specify the menu item for this current window? The menu item from nowshowing.js should be different to other windows. I would also like to specify the creating of menu item once the window is open. Thanks