Have you looked at sharing the Workbook?
TOOLS > SHARE-WORKBOOK
This seems to be the route your asking about, but there are some
limitations that are applied when it is converted to a shared book in
relation to conditional formatting and macros. This is right out of
the MS Excel help files on workbook sharing
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Share a workbook
Create a workbook you want to make available for multiuser editing, and
enter any data you want to provide.
If you want to include any of the following features, add them now:
merged cells, conditional formats, data validation, charts, pictures,
objects including drawing objects, hyperlinks, scenarios, outlines,
subtotals, data tables, PivotTable reports, workbook and worksheet
protection, and macros. You can't make changes to these features after
you share the workbook.
On the Tools menu, click Share Workbook, and then click the Editing
tab.
Select the Allow changes by more than one user at the same time check
box, and then click OK.
When prompted, save the workbook.
On the File menu, click Save As, and then save the workbook on a
network location accessible to the intended users. Use a shared network
folder, not a Web server.
