Sure it can. If you're willing to restrict yourself to fast ethernet speeds (or worse), there's devices that would split up an ethernet connection into 2 pairs for you. However, modern gigabit ethernet needs all 4 pairs.
I've even seen stock cables that only have 4 connectors, and there was a little wierdness with it.
However you'd need to split the cable on both ends for your scheme to work, based off the comments, and its a pretty horrid way to get another 'drop' between two ends of a ethernet cable.
What you want to do won't work, unless you're trying to turn one connection -------- into something like this >--------<. On a university connection, the best you can do is >------- and that essentially just throws half the wiring away for no gain.
Assuming you do this correctly, and don't have wierd slowdowns and other issues like the 4 stranded cable I mentioned. You'd also need to buy unusual hardware (no one really users splitters much) or additional gear you'd use once (ethernet crimping gear!), and a switch makes much more sense here. Its unlikely to be reliable, may fail in strange ways, and might not even work.