Its semantics, but if your front end is VB, then the back end is JET not Access.
There should be no problem in running multiple transactions, it might run a bit slow, you may get the occasional lock problem, but you can handle it.
Just a thought, does your employer have Office 2000,2002, XP or even 2003 (I think). Have a look at the disk with Access on, you may well have a copy of SQL Server. Its a limited function (limited in comparison to the full blown product but still a prety fully featured server) version of SQL Server. I think you are limited to 5, or possibly 10 concurrent connections but worth considering. It's not installed by default, you have to go loooking for it.
Depending on the version of VB you have you may have MSDE or SQL Server -It's not installed by default, you have to go loooking for it - MSDE started shipping in 1999/2000.