Flex :: Multiple Async Webservice Call Requests?

I am using Flex and Actionscript 3, along with Webservices, rpc and a callResponder. I want to be able to, for example, say:

loadData1(); // Loads webservice data 1
loadData2(); // Loads webservice data 2
loadData3(); // Loads webservice data 3

However, Actionscript 3 works with async events, so for every call you need to wait for the ResultEvent to trigger when it is done. So, I might want to do the next request every time an event is done. However, I am afraid that threading issues might arise, and some events might not happen at all. I don't think I'm doing a good job of explaining, so I will try to show some code:

private var service:Service1;
var cp:CallResponder = new CallResponder();
public function Webservice()[code]....

I could ofcourse save the actions in an arraylist, but whose to say that the addToArrayList and the check if other calls are available do not mess eachother up, or just miss each other, thereby halting execution? Is there something like a volatile Arraylist?