I can't see the image your trying to post.
But at a guess your seeing an active signature of 20 and a speed of 10,000 kps correct? If so, you've just met one of Steve newer automated minions.
The Star Swarm. Those aren't fighters, they're gunboats armed with rather large meson cannons and your frigates are toast.
But to answer your targeting question, yes they must be individually targeted.