Have to manually connect to nearest satellite to control wireless music devices

I am using an OrbiRB50 with 2 satellites. There are approximately 12 music zones at my house (using Yamaha musicast, some over wifi, some plugged into satellites).  The point of the system is to play synchronized music in multiple zones and to control volume etc from a single device (mainly an iPhone in my case).  The network uses a single SSID and devices are connected to the closest satellite.  The issue is that the phone often but not always will not see a connected device unless the phone is also connected to the same satellite.  So for example to change the volume in a zone I will sometimes have to stand next to the device and disconnect and reconnect to wifi.  The device then becomes viable but others sometimes disappear that are connected to other satellites  What's going on here?   Is there a setting to fix this?