The QC 35 II can only have two devices connected simultaneously, that's right. You have to go into the Bose Connect app to switch one off and connect another.Plus, I believe that they’re limited to 2 devices for simultaneous connection
Edit - to correct the word Plus being split by the quote
That's the case, when I use my iPhone and MacBook Pro, and the suddenly I want the iPad to join the gang, but I have to disconnect the MacBook first and flip the software switch for the iPad.
Not very annoying but a minor inconvenience at times.