Okay, so my question is, are you planting the dill outside, because dill doesn't like to be transplanted, at that size especially? If you are planting in the garden I would say go ahead and plant all three just as they are. I have planted dill that close before(direct sown) and they do fine.
You could gently tear the pot apart and separate the dill but i don't think it is really necessary and i think they will do better if you just plant the entire pot.
