Hey guys I am looking for sister rivalry in manga only girls not guys okay I know this is rare but I need some.

Conditions:

1) sister is someone who seems to overshadow them or something like that.
2) Friends, and parents favor them
3) main character sub estimated


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Papillon - Hana to Chou is about twin sisters too and fits your description.
Personally, I didn't like this manga very much but who knows, maybe you will?

Spontanously I would have to think of Watashi no Koibito, Kore ga Koi to Iu naraba (But, I just read the description of this one a few days ago, so I can't say much about it) and Chihayafuru, even if the request may not be the main focus. ^^

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"It's like love is a bonus in your life. Even without it, I'm just fine. I don't feel like pointlessly searching for it. You don't have to make yourself unhappy." (Ookami Shoujo to Kuro Ouji)

"Why does it rain?" - "To create drama." (Drops (Andou Yuki))

The only one I think of is Alice 19th