Thanks for the answers so far. I think I might end up designing them just to see if they work, as that seems to be a bit unclear right now.
The reason behind my question is that in the first generation of this missile, I did not know how effective they were, so I wasted a lot of missiles. Then I put the sensor on in the second generation, but it didn't work because it was way too small. In an effort to not waste missiles, I would only send a new load when the first one had already hit. This results in a bit tedious and long combats where I would only launch missiles every six hours or so.
So here comes my idea for the presented generation. I know that it takes less than five minutes for the smaller missiles to hit their target. This means that if I launch the missiles five minutes apart the first salvo will have hit their target before the second has been released. So a sensor on the carrier should then start looking for a new target, if the original target was destroyed.
I'm still worried that 3,7m km is far too short a distance to be functional, but you never know until you test it.