It's not currently possible, since part of using pbExclaim is the playing of the whole animation before anything else. However, because of your question, I've now improved it to allow playing the same animation (typically an exclamation bubble) over multiple events simultaneously. This feature will be in v14 when it comes out. It won't be able to play different animations for different events at once, but I don't think that'd be a problem.
I really like this kind of question. It's a simple topic, simple to fix, and it's something I hadn't considered before so it's new to me.