Is it possible to use qfield on multiple tablets with multiple users, and sync to a single dataset?
The answer is, it depends on your requirements ;)
Currently synchronization is best done on a desktop computer with QGIS using offline editing functionality (possibly involving QFieldSync which is not yet totally stable but is under heavy development).
As long as it is just adding new features or working on strictly isolated areas, this approach is quite solid. What it doesn't have is any conflict management, so different people working on the same feature will overwrite each other's changes.