1) You should split the database, and deploy a COPY of the Frontend (the forms, reports, etc) to EACH user. The users will then connect to a common data source (the Backend).
2) You then perform dev work on your own copy. Once you are ready to rollout the changes, you provide a NEW copy of the FE to each user. If you split the databse, then the data will still be there. You should NOT try to import objects from the new FE to the existing FE.
Note that if you have "local" tables in each FE file, then you'll have to develop methods to transfer that data to the new FE files.