Hello Paul
See the two letter attachments in post #1 of the following thread:-
http://forum.12oclockhigh.net/showthread.php?t=25766
I understand a WW2 "multiple accident" file (involves more than one person in the same accident) and was where one, or more of a crew (including I presume non-service persons) were injured in the same accident.
When I attempted to get the accident file of an aircrew (involving my Grandfather) who all perished in the same crash, I was eventually told later that these WW2 multiple accident files that they had sample searched were found to be "injury only" accidents.
Mark