Nifi - Distributed Databases sending data to a master

I have a potentially large number of distributed database instances that track inventory levels in a number of manafacturing plants.
These plants are not on a single network or anything like that. Each plant has a SQL Server database that tracks certain inventory levels periodically. I would like to be able to aggregate these levels across all plants in a single (think Master) database instance hosted in Azure. (We can then report against this database). I am new to Nifi but I think this might be an ideal use case based on what I am understanding from the docs. Has anyone done anything similar to this?