My understanding is that sound received by the BV7/BS3 via HDMI can not be accessed in link rooms. For this reason we have our Apple TV connected with an HDMI so that I can have 5.1 on downloaded movies but then also connected it with a pair of analog cables so that I can access music from it in the link rooms.
Beovision 7-55 with Beolab 7-4, 9s and 4000s
Beovision 10-40 with Beolab 1s and 6000s
Beosound 1, 5, 2000, and 3000
Beotime, Beotalk, Beocoms