It best to have one computer that host the file and have all other user connect remotely. If you had Filemaker Server, you would have one computer hosting (running server) then everyone else would connect to it remotely. When the user click on Open Remote then the hosting computer with ip address would be listed. You want to use filemaker open remote to share and not just open from the network drive because that can lead to file corruption.
strongly recommend going the extra mile and getting Filemaker Server - we have about ten users and it's very easy to manage
I have used both Server and HOST in the same small office environment. We used the Sever when we wanted to share access to about 25 on a standard MacOS computer that was about 4 years old. No one complained of performance on at LAN or intranet at 1 Gigabit speed.
We recentely switched to a 3 year old Standard MacOS acting as a HOST since we have about 7 users, at the moment and are transitioning to FMP12.
We saw no performance change in our DB's (8 different databases).
Our HOST computer is being used by a Clerical Assistant for their daily work which also includes FMP database work.
ALL Clients must use the HOSTed DB's using Open Remote... [including the Assistant using the HOST computer]
On MacOS, and I feel confident Windows has the same features, we start up the HOST computer automatically at 6AM and shutdown at 11:30PM [you don't have to shut it down, but it is our choice]
On start up or start up from power failure, MacOS is set to run the HOST FMP "start up file". That "Start Up File" is basically the Server that is running first when most show for work.
We will probably purchase Server 12, when all files are running and tested under FMP12, if and only if our client use exceeds 10 on line at a time.
We have both Ethernet and wireless use for the HOST'd DB's.
We use Time Capsule (windows and mac platform usable Apple product) to back up our HOST every hour. I use the Back Up Now feature if I am making major changes in our conversions.
One of our DB is 17GB in size and doesn't reflect a perfomance loss using a HOST set up.
Overall I see no Problems with HOSTing for small office environments for intercompany use.
Even then a simple opening of the "Start up File" take about 1 minute to return to service.