Just in the past few days I accidently discovered an answer to this. I was playing a simultaneous movement game by e-mail with friends. I had assumed up to then that if a group of ships (not in fleet) in one sector moved to another sector, they would all arrive at same time - at least for combat purposes. So I ordered 4 ships - three were identical class - to move to warp point. Unfortunately, there was an enemy ship there and I ended up with 4 separate combats, all of which I lost.
(When I ran a simulation of combat between my 4 ships and the enemy ship, I won easily.)
As an aside, I also discovered that a mine layer will execute its orders to lay mines before combat occurs. Interesting!
