There are discussions under the current answer to Will Curiosity and the Mars 2020 rover be able to communicate with each other via a Mars orbiter? about the feasibility of MRO receiving a message from one rover on Mars and forward it to another.
I seem to remember reading about some NASA (and perhaps NASA + ESA) effort several years ago to make future deep space spacecraft able to intercommunicate in a more flexible way than they did in the past, so that messages between two points can take different routes and various spacecraft can receive and later forward messages to other spacecraft in a straightforward way.
But I can't remember where I'd read this or what it was called.
Am I crazy, or is this actually a thing?
Can rovers play too?
Question: In addition to each's ability to phone home by itself, are NASA (and ESA?) deep space spacecraft now generally able to store and forward messages between themselves?