I saw your question on StackOverflow as well. As the commenters said, it isn't clear exactly what you are trying to do here. If you have database A and database B, it seems to me you would just run liquibase update command pointing to A, and then run it again pointing to B.
I guess the biggest misunderstanding I have is that 'm not sure what you mean by "the database can be updated in real time" - do you mean that there is some other process that is affecting database A that is not Liquibase?
Steve Donie
Principal Software Engineer
Liquibase Community Engagement
Datical, Inc. http://www.datical.com/
Steve Donie
Principal Software Engineer
Liquibase Community Engagement
Datical, Inc. http://www.datical.com/