Yes, I had to setup a series of child campaigns in the Engagement (not transitions).
Trigger: Email Is Delivered IS Email 1
Flow:
Wait 3 days (gotta give them time)
IF Smart List: NOT Opened AND NOT Clicked Email 1, then Stream 2
Your existing list says Opened Email IS NOT Email 1 and that will bring in everyone who opened ANY email other than Email 1, while using NOT Was Opened, will ensure we focus on those who did not Open Email 1. As does the Trigger
You can definitely do this with the Engagement - it may be harder w/o it.
But I wonder why you want to push them to a new Stream so quickly? I had a client do something similar and it didn't really seem to help.