jquery.dialog.js

// accessing all OTHER instances of a widget, from within your widget.

// method one: use your own data store

var instances = [];
$.widget("ui.dialog", {

	_create: function(){
		instances.push(this.element);
	},
	
	open: function(){
		var self = this;

		// call methods on every other instance of this dialog
		$.each( self._getOtherInstances(), function(){
			if( $(this).dialog("isOpen") ){
				$(this).dialog("close");
			}
		});
	},
	
	_getOtherInstances: function(){
		var self = this;
		
		return $.grep(instances, function(el,i){
			return el !== self.element;
		});
	}
});


// method two: store the original element inside the widget's data cache

$.widget("ui.dialog", {
	_create: function(){
		
		// uiDialog is the main dialog container (div.ui-dialog).
		
		// store a reference to the original jQuery element object in it's data cache
		this.uiDialog.data("originalelement", this.element);
	},
	
	open: function(){
	
		// query the DOM for all ui-dialog's, excluding the current instance.
		// retrieve the element the dialog is bound to, and fire the close method on it
		this._getOtherInstances().each(function(){
			var $elem = $(this).data("originalelement");
			
			if( $elem.dialog("isOpen") ){
				$elem.dialog("close");
			}
		});
	},
	
	_getOtherInstances: function(){
		return $("div.ui-dialog").not(this.uiDialog);
	}
});