This makes perfect sense, and I very much agree with what you say about all angels having some sort of connection with all their siblings that simply comes with being an angel, and some of them having an even deeper, special bond with other individual angels. Like Castiel and Balthazar, or Michael and Lucifer.

All this is so very present every time two angels are in a scene together, and that's why it makes me furious when I hear people claim that angels don't love each other, or that Castiel learned the very concept of love or affection or friendship of family from his time on Earth. Angels do love, deeply, just in a different way than humans do.

I'm very glad I'm not the only one who sees it this way.