Hi Bjorn - we are discussing your question here in the room :-). This is
called secondary ring and is actively being worked on. As soon as its
ready it will land in a build but no specific timing yet. Its definitely
an asking we are hearing.
And this is one of two missing fundamental features that are missing. As it is now we can't recommend our Mac users to switch to SfB Mac when they can't hear someone calling from the computer speakers when they hace headphones connected.