Hi, @Dooley, Enda (Enda) Welcome to the Microsoft Q&A platform, thanks for posting the question and for using Azure Services.
As I understand correctly you want to know if there is a possibility of setup a replica for a certain data period
Unfortunately, this is not possible. Think of a read replica as a read-only copy of the primary. However, you can do logical replication where you could do something like this but the challenge will be if the primary server updates a row that is > 3 months old.
Please let me know if you need additional information.
Regards
Geetha