I do have a brother and love him very dearly and we have a really good connection to each other. Still, when watching Charmed, I sometimes felt a little jealous that I didn’t have any sisters because I just loved watching the three sisters together! Their bond is so strong and they share everything with each other (thoughts and feelings, their living place, and ultimately their power).
While I love the bond between all three of them, I think that Prue and Piper’s bond is a special one maybe because Phoebe left San Francisco when Grams died and left the two others alone. But I also think that Piper and Phoebe have a great bond together, which we can clearly see throughout the series. Even Prue and Phoebe who had a rough start in season one developed a really strong bond. I love the episode The Power of Two because the two are all by their owns and I clearly saw for the first time how much their bond had grown.