under "messages" it already has to be unique because it's in a map.
but the "messagegroups" attribute could cause dups. We may not be able to make it a MUST, so SHOULD might be good enough and just warn people.
Need to revisit this since this would not work in cases where there are two message definitions for the same event(message) but in 2 different formats (xml vs json).
under "messages" it already has to be unique because it's in a map. but the "messagegroups" attribute could cause dups. We may not be able to make it a MUST, so SHOULD might be good enough and just warn people.
Proposal: STRONGLY RECOMMENDED that they do it