Adding a shared calendar from office 365

Now we need first to add delegation permissions on the target(co-workers) calendar and then we can see it.

As I customer I would expect to be able just to browse all employees calendars that are available to me and add one as it can be done in Outlook. (And for this co-worker does not need to set a full delegation!)
Default delegation does not work . It looks it has to be name by name!!