In our app we need to send one message to a group of users (it could be 10 users or 1500+ users). When we were using parse we were creating channel for every user based on it's user_id from our system. And when we needed to send a push notifications to a group of users we just sent array of channels (user ids) to Parse and it was working. So my question is it possible to do something like this using UA? I guess named users feature is what we need but I couldn't find a way to send push notifications to array of named users. I think we could use OR operator but https://support.urbanairship.com/hc/en-us/articles/213492183-What-are-the-limitations-to-the-Urban-Airship-Engage-API- here you say that using > 1000 selectors is not recommended. Why? Would it be super slow?