Is there a way to program a deadspot before control mixing starts?

[Punkwood2k]

Toying around with 250Racers. Through trial-and-error, I figured out how to mix my Roll+Yaw controls in the transmitter. But I'm wondering if there is a way to create a "deadspot" in the Roll, before the Yaw mix comes in? Mostly for small lateral moves while hovering/landing. Right now, any Roll/Lateral move includes the automatic Yaw, which makes it hard to hold a steady position when landing/taking off/hovering..

Is there a way to program this?

I am using a FlySky T6 transmitter and LibrePilot.

thanks!