Sorry it is just two standalone systems with an eircom router. There is a back office system where software is running and a front end system where staff are using the software being run off the back room system.
The firewall has to be turned off between the two systems as the software won't work if a firewall is activated.
I have been looking it up and what I've come up with is either installing an Application called Access Manager where you can set retrictions to systems or user.
The other option is running the command mmc and setting Group Policies from there.
Any advice would be appreciated I hope I gave enough info.