Multiple user write access to an Excel 2010 file

Hello, I am wondering if anyone knows of a way to set up an Excel file (or our individual Excel programs) so that multiple people can have the same Excel file open and edit it at the same time? I know that you can do this with Google docs, but we can't upload company data to an external cloud. I also understand that each user will want to save often and the updates won't be immediate, but there's only a few people that will need to edit this document, so I don't think that should be an issue.

Thanks,


Andrew