IQ again, I need some logica advices

Thanks to you I can now exchange IQ packets between some clients and a server! Now, for my program, I need a sequence like this:

1)Server sends IQ packets to every connected client.

2)Every client has to answer to that IQ packet with another IQ.

3)Server has to wait for every client to answer before progressing.

Now, as I’m using IQHandler, I should make some kind of synchronization over an asynchronous mechanism (by the way I can’t understand who will use the IQ returned by the.IQHandler handleIQ() method…).

Before I start making something which would probably already exist I ask you: is there another class or component which allows to make a “blocking receive”?

I.e.

//server side

something.waitForIQ();

//unlocks just if IQ comes