well, as you claim to know everything about computer..\LOL
Your are talking about PATA, and you proberly wont be able to do that on your old computer as its a fairly new include on modern computers.
What you can do is either;
set up a FTP server or your own video server to stream content or just store video ( I guess youre all knowing so I wont have to tell you how to do that)
Set them up as a Shared drive, You need to right click on the drive to set it up,( as your all knowing I wont need to tell you about how to set up the security)
I would set it up as shared drives, maybe cluster the systems
Need Pro Computer advice?