Dear all,

In my business we are based in different parts of the world. and we want to work on the same excel file simultaneously.
I can't find a program for this.
Google Docs and Windows Office Live both don't support everything in the excel file (data validation etc.),
Dropbox and similair keep creating 'conflicted copies'.
So a solution for my problem would be a netbased program wichs lets only one person in a time working on the file.
Let me give an example:
person A,B and C have excess to document X, They only can make changes to this document when connected to internet.
During the time person A makes changes document X is not availeble for person B and C (maybe read-only).

Our local server works like that but i can't find a internetbased program which does the same...