This is very useful if the (world) premiere network is not available to you, but the alternate is.
Example: Julius Caesar: The Making of a Dictator premiered today on BBC 2. It is available to most Europans at a weekly frequency.
But Britannians can stream all 3 episodes right now on iPlayer.
The way I imagine this could work quite intuitively is by filtering on My followed networks and My followed web channels. They are already a feature of the Calendar view filters. And would be a welcome addition to the Watchlist as well.