Hi. If that app supports HID we could add support for it (kind of making Flic act as a keyboard). So for example we can simulate the key left/right etc.
If it does not support HID you could try to contact the authors of the Audible app and request them to add such a feature.
@bambi2000 Thanks. I did manage to get the basics working (as well as find the streams for P3 and P4 🙂 ). I also managed to group players by setting CurrentURI of the "slave" IP to the UUID of the "master".