Sorry. I do not think this is possible. The web  file is, in effect, an image
of the excel  spreadsheet. It does not have the functionality. To do what you
want to do you will need to build a web application, perhaps using javascript
or vbscript in an ASP.net web page. In effect it means  starting again from
scratch.

Another possibility is to put the workbook on the internet  and allow your
colleagues to download copies.

You could also, perhaps, use sharepoint - but I am not in a corporate
environment and have never tried it.