I run a smallish job placement office with 15 workers who, for various
reasons, should not have access to each other's records.

Each member of my staff has an Excel spreadsheet showing all of their
clients and data about each client. I need to create a spreadsheet that shows
all of the information from the various spreadsheets (which are all similarly
formatted). Additionally, if at all possible, we would like to have some
information flowing the other way.

As an example, let's assume there are two spreadsheets, A and B, with two
collums of information: Name and Address. I would like to create spreadsheet
C that has all of the Names and Addresses from A and B. Next, I would like to
have info in C displayed in A and B, say Phone Numbers. So, the persons using
A or B can view all information on their names and change addresses (but not
phone numbers). The person using C can view all information from both A and B
and can change phone numbers. I don't care if person C can change addresses
or not.

If this cannot be done, is there another setup that can give us similar
results?

Thanks, in advance, for any assistance!