Hey @kevinclcn
Hope you are doing well!
In my opinion, re-using schemas is all about enabling modular-data-infrastructure. So, if you have created one schema and used it in two data sets. And say that you have enabled batch ingestion to both data sets. Then, when a data ingestion occurs, Adobe would utilize same schema for both the data sets separately while receiving and storing the data.
So, there shouldn't be any conflict in looking up the fields or fields groups while ingesting data, as long as schema is intact and source connection is unchanged!
Best,
Kishore