In another system I used previously, we were able to add release notes directly to the Story and Bug tickets. We were also able to use a pick list to specify who the release notes would be applicable (Internal, External, Support, Sales, Training, Customers, etc.)
This way when the tickets were written so were the release notes. Then when we were ready to release we could pull all of the release notes at once for creating the appropriate documentation for the scheduled release.
Is there anything in Jira we could use for that?