The best way to share data amongst a group of users is to set up a Shared Database. This is an SQL database installed on your own in-house server that integrates seamlessly with Geneious via the Shared Databases icon in the Sources panel. Users can drag and drop files from their local database into the Shared Database to share with colleagues, and each user's access to individual folders within the database can be controlled by the server administrator.
See chapter 19 of the Geneious user manual for further details.
The local database (i.e. the "Geneious X.Y Data Location") cannot be shared by multiple users.