At the moment in jQuery (and UI as well, see explode effect for prime example); there is no possibility to execute multiple animations in parallel and guarantee that they will execute in sync.
At http://dev.jquery.com/ticket/6281 I proposed an implementation to effectively enable synchronization; but question arises if this should be in Core or in UI. Thus I need to ask you what you think, and also if my implementation is the right™ way to accomplish this.
An example of this issue can be found at  http://js.azatoth.net/test/slotted2.html