Pulmonaria is incredibly easy to divide. Six plants can quickly become 24.
Just dig up the plants and using a sharp knife cut in half and then cut in half again. Keep the chunks together and plant, even the bits with no leaves or leaves with no roots.
It works best in the spring. I don’t bother removing the blooms, it doesn’t seem to be helpful. By summer all these leaves will wither away and attractive new leaves will form.