Rather than using Signals, why don't you just nest your Sequences that you want to run? Something like this:
var sr1:SequenceRunner=new SequenceRunner(this);
var sr2:SequenceRunner=new SequenceRunner(this);
//add some sequence steps to sr1 here
sr1.addStep(new SequenceWaiter(someEventDispatcher, someTriggerEvent, 10000));
sr1.addAssertHandler(
function(event:Event, passThroughData:Object):void
{
//add some sequence steps to sr2 here
sr2.addStep(new SequenceWaiter(anotherEventDispatcher, anotherTriggerEvent, 10000));
sr2.addAssertHandler(
function(event:Event, passThroughData:Object):void
{
//do some assertions here
}
, null);
sr2.run();
}
, null);
sr1.run();