Yes. Multiple NextD Players can be controlled by a single NextD Remote app.
The NextD Remote app can only connect to one NextD Player at a time. To switch the connection to another NextD Player, simply click on the menu button (3 vertical dots) on the upper right corner of the NextD Remote app, then click on "NextD Player Select". The NextD Remote app will then automatically scan for all available NextD Players on the network and ask the user to choose one to connect.