Excel calculators available on intranet

[Senior Paper Monitor]

I have an intranet site in development.

This is 'hosted' on my desktop PC (actually sits on a shared NAS drive) and accessed on the network by up to 6 colleagues.

I have some fairly complex (but not large file size) excel calculators for various processes which will be used by any of those colleagues. There could be a need for more than one to use a given spreadsheet at any particular time, but as there should be a copy of the calculation placed on the client's file then disciplining people to 'save as' as soon as they open it should be possible.

With the above in mind what is the best way to integrate these (the 'masters' are also hosted in a specific file on the NAS drive) into the site ?