MCD 5.0 will introduce a new `Multi-device User` license. This will license the Multi-device Group and you can fill the group up with up to 8 devices or numbers without licensing them separately. The new group works very similar to Personal ring groups (Dynamic Extension) but you have one busy all busy set (incoming and outgoing).
So, one User, one licence and up to 8 different devices or numbers all ringing at the same time.