How to put 2 different key signatures on a grand staff?

[prokofiev89]

I am writing a piano piece and there is one part where I have some bi-tonality and want to put 2 different key signatures on the grand staff. An example would be to have the bottom staff for left hand be in Bb minor and the top staff for right hand be in a minor.
Is there a way to do that?
Thanks!

[vilnai]

There's a 'one staff only' option in the Key Signature dialogue

[prokofiev89]

There's a 'one staff only' option in the Key Signature dialogue

Thanks!
Never noticed it before haha

[MorielGeorg]

There's a 'one staff only' option in the Key Signature dialogue

A very big thank you!