I would write Triggers on DatabaseA.TableA.

>Hi,
>I need to replicate data from tableA, databaseA to tableB, databaseB. The table structure of both tables may not same. I need to do some custom transformation before move it from table A and B. Also, I need the records in table A to be inserted to tableB if not already existed and update it if it is existed.
>
>Can I use SQL Server Replication or DTS to achieve this?
>
>Thank you