Due to the second marriage of her mother, lively high-school student Amamiya Matsuri becomes the younger sister of the super popular idol group of triplets "Terzetto"! Star celebrities for stepbrothers?! A forbidden secret love with a perfect prince ★

From Shoujo Crusade:

In the world of the high society , it is expected that each member of every family has their own personal butler. Himeoka Kokoro is a natural tomboy with a knack for sticking her head into trouble. Kokoro hopes to be able to hire a butler for herself, but only temporarily so she can partake in the nationwide "Miss Princess" model search. She is determined to win the competition because of a promise she made but runs into problems on the way. She incidentally saves an old lady who turns out to be the President of Butler, the most prestigious butler agency in Japan. The old lady decided to help her with the model search & Kokoro is suddenly faced with four good looking butlers to help her on the way to winning the title "Miss Princess".

From Divine Sanctuary:
Yuzuki has a crush for her super kind and cool brother, but she has her heart broken when he brings his girlfriend home one day. The next day, by chance, she bumps into a guy who looks exactly like her brother! What is this feeling that she has for him? Is it just because he looks like her brother, or is it...?