No, combat is one on one, usually but not always to the death of one of the two ships involved.
As an important note, especially if you have a decent but not outrageous advantage over your opponent, you always want to have two or more ships of your highest defense rating in a stack. Why? I think, but can't prove, that if you have multiple ships with the same defense rating, it uses the one with the most HP. Now, if you've got one dreadnought that has a slightly better defense than 9 others, that one will get hammered until it is destroyed, without touching the rest of the stack. On the other hand, if you have 10 dreadnoughts with an equal defense, the attack will hit whichever one has the highest HP, which may knock it off the top of the list. Now, why this is important is because you're distributing the damage between more than one ship if you're taking multiple attacks, so rather than repairing damage on one ship, you're repairing more than one ship, each at the rate that you'd be repairing just the one. So, if you've got a 10-dreadnought fleet that repairs 2 HP a turn, the enemy has to do 20 HP of damage just to break even, instead of just 2 HP.