How could we seperate a group?

One of the important principles in warfare, and even moreso in tactical games, and even moreso in this game, is to seperate an opposing group that is united in force and able to concentrate its fire. Therefore, the wise admiral is one who can keep his forces together while separating the opponent’s.

So let’s theorize. Put yourself in the perspective of a captain or fleet commander ready to engage the enemy. What are some tactical methods that could theoretically be used to separate a tight formation of starships?

Here’s my list so far:

  1. Get some of them (all of them?) to chase you
  2. Get some of them (all of them?) to flee
  3. Pull them apart with tractor beams
  4. make their area of space extremely unpleasant place to be (see idea # 2)
  5. magnetize their hulls
  6. slow some of them down or disable some of them

edit: some more ideas:
7) as with #3, but using a nearby gravity well to trap some of them, perhaps through artificial means of directing gravity
8) maneuver ships in the heart of the enemy formation, perhaps with cloaking devices, teleporters, or an FTL drive
9) as #8 but with fighters or mines or small black holes instead of ships

All of these have risks, and some seem like they would work better than others, but we’re just brainstorming here.

Any ideas to add?

A pincer manoeuvre - so instead of attacking head on, you attack left and right of the formation, the ships will separate into 2 separate teams
This is countered by placing every ship into formation on a single leader - which means you have to take out the leader first.

Remember that only the challenger can take advantage of all those things. As it stands currently, a series of decoys does just that.