Sync and Round Up External Dates Merged

Our internal and external release dates are always the same and we sync that information directly from JIRA. We also round up the release dates (let's say to the nearest quarter). However, when the internal date changes, the external date does not sync with it and round it up. So, when the internal date moves, the viewers/consumers of this information who only refer to the external date don't see the shift - which is a problem for us since we were hoping for this to be completely automated. Ideally, I'd like for the external dates to move with the internal dates and also continue to be rounded up to the nearest month, quarter etc. based on the selection made.