With a conventional LAN with a fileserver, it is already easy to keep one spreadsheet. I don't think people can edit it together.

MS Access is much better for allowing simultaneous editing, especially (IIRC) if it's backed by an RDBMS, since it will use row level locks.

My previous employer had several databases with read-only web interfaces, but Access editing interfaces. They're very fast to develop, and support all the usual database features (constraints, keys, search etc), and could be set to load a form-editing view by default.