[bshanks]

Not a physicist but isn't it the case that any two observers can still compute at what time the other person perceived any given event, if they know each other's history of travel and the history of travel of the event?

So you would just have to agree that one observer's clock is the "master clock", and then everyone translates their local clock time into the corresponding master clock time (and all timestamps are written with respect to the 'time zone' of the master clock).