Kewl you shloud come up with that. Excellent!

That's just what Sundera does - it enables spreadsheet users to identify specific cells/ranges which they want to share with others, as well as to receive automatic updates from others' cells/ranges.
Sundera's work is the closest one gets to seamless work with distributed spreadsheet data.

Sundera has invented a technique to update shared data within applications and documents in real time over the internet. The technique is secure and can be applied to any form of data storage including office documents and databases.
Sundera’s first product is a Microsoft Excel plug-in that lets any number of users of a spreadsheet selectively update data cells or see updated data in real time.
Cute... Though, Sundera Inc is still in beta stage.