Google Play Music has just been updated on Android to allow users to save radio stations for offline listening.
The update lets users pin entire radio stations to their device for listening to when an internet connetion isn't available.
Users can also remotely manage the devices which have access to the collection with a "play next" option to queue up a song you really want to hear.
The Google Play Music update has begun rolling out so might be available on your device now. But as is the way with these updates, it won't reach everyone at the same time so you might need to sit tight for a while before you can take radio stations offline.