ExtJS4 custom events when dynamically create components

Question

I have a problem. I use in my app observable pattern to manage custom events:

var app = {};
app.Event =
{
    _observers:[], 
    subscribe:function (event, obj) {
        var c = obj || null;
        if (c) {
            this._observers.push({event:event, obj:obj, id:obj.id }); 
        }
    },

    fire:function (event, data) {
        var item;
        for (var i in this._observers) { 
            if (this._observers[i].event == event)
            {
                item = this._observers[i];
                item.obj.fireEvent(event, item.obj, data); 
            }
        }
    },


    unsubscribe:function (event, obj) {
        for (var i in this._observers) { 
            if (this._observers[i].id == obj.id) 
            {
                this._observers.splice(this._observers[i], 1)
                break;
            }
        }
    }
}

I also have one big custom component (call it 'Mr. Big'), that contains child custom components. And these childs fire to each other custom events. Problem that at my application I can have more than 1 instance of 'Mr. Big' and each 'Mr.Big' will be created dynamically. Childs also created dynamically.

Ext.define('Mr. Big',{
 extend:'ME.view.portal.portalItems.base.Panel',
...
items: ['child 1','child 2']
}); 

Ext.define('child 1',{
...
 listeners:{
customEvent1: function(ev, data)
{
...
}
initComponent: function()
{
...
app.Event.subscribe('customEvent1',this);
...
}
}

Ext.define('child 2',{
...
 listeners:{
customEvent2: function(ev, data)
{
   app.Event.fire('customEvent1',anyData)
}
initComponent: function()
{
...
app.Event.subscribe('customEvent2',this);
...
}
}

For example, I have 2 instances of 'Mr. Big'. What I need to do, if I want that customEvent1 of child 1 of 'Mr. Big 1' won't be fired by child 2 of 'Mr. Big 2'.

One of my solution is: use unique ID for Mr.Bigs and its child components and in handlers before perform any operation write:

 if (this.UID != data.UID)
 {
     return;
 }

BUT: if i have 3 or more 'Mr. Bigs' and in each of them I have 9 childs my custom event will be fired so many times that I think that I have problems of speed of my app.

Help me please!