If you got a good design (which means you are skilled at this), and you do
this right, then that number is certainly possible.
Depending on your network, you might have to put the data part on sql
server.
The first thing to get right here is to split your database. You can read
why you split here:
http://www.members.shaw.ca/AlbertKallal/Articles/split/index.htm
And, of course, you need to be aware of what kind of network you are going
to use here.
You can read about using ms-access on local area, and wide area networks
here:
http://www.members.shaw.ca/AlbertKallal/ridesrpt/ridesrpt.html/Wan/Wans.html
I would say that if you STARTING number of users is to be 25, then I would
likely make the effort, and use ms-access with sql server in this case.
If your starting number of users is 5-10, and you think it will grow to 25
over time, then ms-access with jet is a reasonable start. So, the number of
users you have, and will start out will dictate your choice as to which
database to use with ms-access. At least with ms-access you have a choice
as to what database system you plan to use with ms-access.