The are a number of problems with trying to synchronize your control of multiple characters. First, each character is subject to things out of your control:network lag, differences in processors, micro delays in keyboard/mouse input, etc. Another problem you have to overcome is getting every character perfectly, and I do mean PERFECTLY, lined up. This is pretty much impossible. Here is a crude visual aid to help you see what you have to overcome.



If you're in the green interior circle, it may seem like your characters are lined up, but the farther you move out towards the red circle and beyond, the more pronounced any variation becomes. Even if one of your characters is off by a tenth of a degree, it will take no time at all before he's running off from your other characters.