Deborah wants needs a database and wants to be able to have a limited number of people in the company to share it. Microsoft Office can do it, but it usually uses a locally run Exchange server.
Leo suggests looking at this tech note from community.office365.com. Leo suggests creating a spreadsheet and then see if it can break. Leo did it with Google Docs and they got 150 current users before it started to refuse connections. So Google Docs would work as well.