Did Sri Rama had an elder sister by name Shanta?

[Padmanabhan.J]

Did Sri Rama had an elder sister by name Shanta? I may be wrong, please enlighten me.

Shanta is said to be the daughter of Dasharatha and given to Romapada in adoption, and Rishyasringa marries her alone.
This is what Sumantra says to Dasharatha at 1-9-19.

http://www.valmikiramayan.net/bala/sarga11/bala_11_prose.htm