Okay a question on networking, i am very inexperienced and i bow to the experienced

ray: at least i'm asking to learn
Here's the setup: 1 managing computer, and 1 file computer are currently linked separately from each other (But at the same workspace). I am wanting to add two more 2000 computers and have each one be able to access both the managing computer and the file computer from their workspace. And still be able to use the managing computer and file computer from their current workspace. Is this multiple login possible and what would be needed? or is there another way to do this to where the three workstations would be able to access these two computers all at the same time for files and programs? Would a server maybe need to be added? hubs? wiring?
What do you guys think, all the help is appreciated! Thanks!