Aaaa this is actually fairly simple.
1. Make sure they are the computers are useing the same protocol (TCP/IP or IPX or Netbui). Recommend only using one protocol (pick one).
2. Make sure all the machines are in the same workgroup. Sometimes you have to remove a the machines from a workgroup, then back again. You shouldn't have to, but for some reason it works. Also when joining the workgroup, make sure you spell and capitolize the same way each time. Again, you shouldn't have to, but for some reason it works.
You should be good to go.
One thing to keep in mind, if the all the machines are shut down at night and fired back up in the morning. You may not browse the workgroup for a bit. The reason is when a machine is fired up (and all are 95, 98) an election is initiated to see who will be the "browse master". Then when one machine is elected, it takes a bit for the other machines to register. Now if you have an NT/2000/XP machine sitting there, it always wins as the browse master.
There are registry tweaks that can be made to set one machine to always be the browse master. Go to MS support and look it up, if you are inclined.