Residency question when filing jointly but in different states (CA and Kansas)

Hello Everyone,

 

I'm on H1b and my spouse is on F1-OPT. I'm domiciled in CA and she is in Kansas. We went through the TurboTax filing and finished the Federal and State details. However, when it comes to state, the CA filing asks us to file as residents together and then because of this the Kansas state filing says file as non-residents for both of us. My entire earning is in CA and her's in Kansas, so the numbers are easy to separate. Just wanted to know if this is correct. I read online that CA does not allow individual filing if my federal is filed as married and filing together. 
Also, I believe we both need a sign a letter saying we wish to consider my wife as resident alien for tax purposes. Do we also need to mail this letter to the state filings?

Thank you!